Abasia

The inability to walk, especially when it is caused by mental disorder.

Abdomen

The hind part of insects, spiders, etc. The belly, including the nutritive organs.

Aberrant

Diverging from normal type.

Aberration

The non-convergence of rays of light to a focus. The apparent displacement of the true position of a heavenly body.

Abiogenesis

Spontaneous generation.

Abnormal

Deviating from type.

Aborigines

The inhabitants of a region, or, in some cases, the plants and animals, found by colonists. Literally, those that have been in the land from the beginning of things.

Abort

Have premature delivery of a child. Remain undeveloped or sterile, or dwindle away.

Absolute

Pure. The absolute, philosophically speaking, is final and total reality.

Absorption

Disappearance through incorporation in something else. The solution of a gas in a liquid is called absorption. Rays of light may be absorbed in some mediums.

Abstract

Theoretical, aside from particular instances.

Abulia

Weakness of will.

Abyssal

Relating to the depths of the sea.

Acaulescent

Apparently stemless.

Acceleration

Rate of increase of velocity per time unit. Rate of change of the velocity of a chemical reaction. The acceleration of a star is the time it gains daily over the sun.

Accident

A property which is not essential to our conception of a subject.

Achene

A small, dry, indehiscent, one-seeded fruit.

Achromatic

Colorless, transmitting light without decomposing it.

Acid

A substance that neutralizes and is neutralized by a base, and which contains hydrogen. A compound that produces hydrogen ions when it decomposes in aqueous solution.

Actinium

A radioactive substance, believed to be an element.

Actinozoan

One of a class of coelenterates including the corals.

Aculeate

Having a sting, prickly.

Acuminate

Tapering to a point.

Adiabatic

Maintaining a constant temperature.

Adrenalin

A crystalline substance obtained from suprarenal extract.

Adsorption

The condensation of dissolved substances on the surface of a liquid or solid.

Adventitious

Not in the usual place, as a root.

Aerial

Atmospheric.

Affect

Disease, emotional complex.

Afferent

Conducting inward.

Agoraphobia

The morbid fear of public places.

Agronomics

The science of crop production. The scientific management of land.

Agrostology

The study of the grasses.

Air pump

A pump for forcing air into, or taking it out of, hollow places.

Air

The atmosphere, a gaseous substance of which oxygen and nitrogen are the principal constituents.

Albino

An animal, especially a human being, characterized by the congenital absence of coloring pigment in the skin, hair, and eyes. The typical albino has very light skin and hair and pink eyes.

Albumen

A substance, usually edible, found between the skin embryo of seeds.

Albumin

A class of proteids found in blood serum, milk, and muscle.

Alcohol

Ethyl alcohol, the substance which causes intoxication, and a whole class of substances which are similar to it. They are hydroxides of organic radicals.

Alga

Seaweed. Chiefly used in the plural: algae.

Alkali

Caustic hydroxides which form soluble soaps with fatty acids and turn red litmus paper blue.

Allotropy

Variation of physical properties without change of substance. Carbon, for example, may exist as lampblack, graphite, or the diamond.

Alloy

A mixture (not a compound) of metals.

Alluvium

The deposit of earth and other materials by the mechanical action of running water. More familiar is the adjective: alluvial.

Alpha rays

Becquerel rays which have less power of penetration than beta rays but greater power of inducing conductivity in gases.

Alpine

Relating to a mountain district so high that it has arctic climate.

Alum

A double sulphate of aluminium and potassium. Other sulphates of similar crystalline form are also known as alums.

Aluminium

A metallic element. The spelling given is the usual one in Great Britain, and it is also the one employed by American chemists. In ordinary use in the United States: aluminum. The symbol: Al.

Amalgam

An alloy containing mercury. To amalgamate is to form an amalgam.

Ammeter

An instrument for measuring the strength of electric currents in amperes.

Amorphous

Uncrystallized.

Ampere

Sometimes spelled: ampère. The unit of electric current, the current that one volt can send through one ohm.

Amphibia

A division of Vertebrata, intermediate between reptiles and fishes, including the frog. The study of Amphibia is known as amphibiology.

Amplexicaul

Encircling or clasping a stem.

Anabolism

Constructive metabolism.

Analogy

Functional correspondence between parts of different origin and structure.

Analysis

Resolution into simple elements, as by chemical processes. In mathematics, algebraic investigation.

Anandrous

Without stamens.

Anaphylaxis

Excessive susceptibility to an albuminous substance.

Anatomy

The science of bodily structure.

Anemograph

An instrument for recording the direction and force of wind.

Aneroid barometer

A barometer in which there is no liquid, the pressure of the air being measured by its action on the elastic lid of a box in which a partial vacuum has been created.

Angiosperm

A plant of a class which has its seeds in a closed ovary.

Anhydrous

Without water of crystallization or water in general.

Animal

A living being distinguished from plants in that it is capable of voluntary motion and sensation. Some recent investigations appear to lead to the conclusion that other differentia will have to be adopted. The human being, incidentally, is an animal, although popular language sometimes distinguishes man from the animals.

Animalcule

A minute animal, usually one which cannot be seen with the naked eye.

Anion

A negative ion.

Annual

A plant that lives only for a year.

Annulate, annulated

Ringed.

Anode

A positive electrode.

Antenna

Feeler, sensory organ found in pairs on heads of insects and crustacea. Irritable processes found in some male flowers. An elevated conductor for receiving or transmitting electric waves. Plural: antennæ.

Anther

The part of the stamen which contains the pollen.

Anthropogeography

The science which treats of geography as applied to man. That part of anthropology dealing with the effect of the environment on human beings. There are a number of compounds beginning with anthro-. The meaning may often be understood by remembering that the Greek word anthropos means man, not as opposed to woman but as excluding the non-human.

Anthropology

The study of man as an animal, with respect to race, distribution, culture, and social organization.

Anticlinal

Forming a ridge with strata leaning in opposite directions from an axis. Having an upright spine toward which spines on both sides lean.

Anticyclone

An outward and rotary flow of air from an atmospheric area of high pressure.

Antidote

A medicine used to counteract a poison or disease.

Antimony

An element of metallic appearance. Symbol: Sb.

Anus

The posterior opening of the alimentary canal.

Apetalous

Without petals.

Aphasia

Loss of speech from a brain injury.

Aphelion

The point in the orbit of a planet or comet farthest from the sun.

Apheliotropic

Turning away from the sun.

Apogee

The point in the orbit of a planet or the moon where it is farthest from the earth.

Aponeurosis

The flat, dense connective tissue covering and forming the attachments of certain muscles.

Aquatic

Growing or living in or near the water.

Arachnida

A class of animals including spiders and scorpions.

Arachnoid

Covered with long, thin hairs. A serous membrane enveloping the brain and spinal cord.

Arboreal

Living in or connected with trees.

Archean

Also: Archaean. Relating to the earliest geological period.

Archeology

The study of prehistoric antiquity, or sometimes of antiquity which is not prehistoric.

Arenicolous

Living in the sand.

Argon

A gaseous element found in the atmosphere in small amounts. Symbol: A.

Arsenic

A semi-metallic element. Symbol: As.

Art

Skill of various sorts. Knowledge from the practical point of view. H. W. Fowler distinguishes it from science: “Science knows, art does; a science is a body of connected facts, an art is a set of directions; the facts of science (errors not being such) are the same for all people, circumstances, and occasions; the directions of art vary with the artist and the task.” According to the Oxford English Dictionary: “The distinction as commonly apprehended is that a science is concerned with theoretic truth, and an art with methods for effecting certain results. Sometimes, however, the term science is extended to denote a department of practical work which depends on the knowledge and conscious application of principles; an art, on the other hand, being understood to require merely knowledge of traditional rules and skill acquired by habit.”.

Articulation

A joint, as between bones or parts of plants, especially between parts which may separate at any time.

Ascendant

Rising toward the zenith.

Asexual

Without sex.

Assay

A sort of analysis, especially of metals.

Association

Mental connection. The word has also three or four meanings in chemistry, which cannot be explained briefly.

Asteroid

A minor planet.

Astronomy

The science of the heavenly bodies.

Astrophysics

The science which deals with the constitution of the heavenly bodies. It is a branch of astronomy.

Atmosphere

The gaseous envelope about a heavenly body. Especially the air which surrounds the earth. As a measurement, a pressure of fifteen pounds per square inch.

Atom

The smallest particle of an element that enters into combination. According to old definitions, it is indivisible.

Aurora

A luminous atmospheric phenomenon. The aurora borealis radiates from the north magnetic pole, the aurora australis from the south magnetic pole of the earth.

Avogadro’s Hypothesis

The assumption that equal volumes of gases contain equal numbers of molecules if conditions of temperature and pressure are the same. It appears to be close to the truth.

Axiom

A truth which is considered self-evident.

Bacillus

One of a sort of rod-shaped bacteria. Loosely, any bacterium. Plural: bacilli. The Oxford English Dictionary distinguishes bacillus from bacterium, “with which it agrees in its rodlike form, and characterized by its larger size and mode of reproduction.”.

Bacterium

More familiar in plural: bacteria. A group of vegetable microörganisms. Not all cause disease.

Barbarian

Of a civilization intermediate between one which is called savage and the most complex forms.

Barium

A silver-white element, classed as a metal. Symbol: Ba.

Barometer

An instrument used to measure atmospheric pressure, and thus to predict storms or determine altitudes.

Base

A substance which can neutralize acids to form a salt. The term includes alkalis. Part of an organ (of a plant or animal) attached to another organ which is more central.

Batrachia

An order of amphibians which have no tails in the adult stage.

Battery

A system of cells (sometimes used for a single cell) which changes chemical energy into electricity.

Becquerel rays

Rays emitted by radium and other substances which are susceptible to deflection by electricity and which electrically charge other bodies.

Behaviorism

Watson’s psychological system. Opposed to introspective psychology, and it emphasizes the physiology of human behavior.

Bessemer steel

Steel made from cast iron by a process which burns out carbon, sulphur, and phosphorus.

Beta rays

Becquerel rays which are apparently identical with cathode rays.

Bichloride

A compound in which there are two atoms of chlorine in the molecule.

Biennial

A plant that rises one year and flowers, fructifies, and dies the next.

Binary

Composed of two elements.

Biochemistry

The chemical study of living organisms and their products.

Biology

The science of living organisms.

Biophore

The indivisible unit of life. The biophore cannot support life if split up.

Bird

One of a class of feathered and warm-blooded vertebrate animals.

Bisexual

Pertaining to, or containing the organs of, both sexes.

Bismuth

A metallic element. Symbol: Bi.

Boron

A non-metallic solid element. Symbol: B.

Botany

The science of plants.

Boyle’s Law

The theory that the pressure exerted by air is directly proportional to its density. This is now believed to be true only approximately.

Brachycephalic

Pertaining to skulls of which the breadth is at least four-fifths of the length. Short-headed.

Brass

An alloy of copper and zinc.

British Thermal Unit

The amount of heat which is capable of raising the temperature of one pound of water by one degree Fahrenheit. The usual abbreviation: B.T.U.

Bromine

A liquid element. Symbol: Br.

Bronze

An alloy of copper and tin, usually with small amounts of zinc.

Brownian movement

A movement of minute drops of oil suspended in stagnant air, apparently due to molecular motion.

Bunsen burner

A sort of burner much used by chemists, within which air and fuel gas are mixed.

Burn

To oxidize in such a way that heat and light are produced.

Cadmium

A metallic element. Symbol: Cd.

Caesium

A metallic element. Symbol: Cs. It somewhat resembles potassium.

Calcium

A metallic element. Symbol: Ca. Compounds of calcium are common, but the element is not to be found in a pure state.

Calculus

Solid concretion in the body. A branch of mathematics, differential and integral calculus, which deals with problems of constant variation or motion, and which has been of great importance in modern science.

Calorie

The unit of heat, the amount of heat necessary to raise the temperature of a gram of water one degree Centigrade. This is the small calorie. Confusion sometimes results because the large calorie, which is one thousand times the small one, is called simply the calorie, without any qualification, in discussions about food. It is sometimes known as the great calorie. The small calorie is best called the gram-calorie.

Calorimeter

An instrument for measuring quantities (not degrees) of heat.

Calyx

The outer case of a bud.

Cambrian

Relating to the lowest of the Paleozoic rocks and the earliest part of the Paleozoic period.

Candlepower

The unit of illumination, measured by a standard candle. The illumination produced one foot away from a standard candle is the candle foot.

Capillarity or Capillary attraction

A phenomenon best illustrated in very slender (capillary) tubes, in which the liquid rises, or, if it does not wet the tube, sinks. In the latter case we speak of capillary repulsion.

Capital

In economics, wealth employed for the purpose of production.

Carbolic acid

Phenol, not a true acid.

Carbon

An element which exists in three allotropic forms. Symbol: C. The oxides are important, and there are many organic compounds.

Carboniferous

Pertaining to a Paleozoic (geological) period following the Devonian.

Carburetor or Carburettor

A device which mixes air with petroleum vapor, or one which puts illuminants into water gas.

Cardio-

Heart-, in many combinations.

Carina

A ridge-shaped structure.

Carnivora

The flesh-eating mammals.

Carpel

An organ which is part of the pistil.

Catabolism

Destructive metabolism.

Catalysis

The effect produced by a substance (called the catalyst, the catalytic agent, or the catalyzer) which aids a chemical change in other bodies, undergoing no change of its own.

Cathode rays

Rays discharged from the cathode (negative pole) of a vacuum tube. They are considered streams of electrons, which may be projected at a velocity of 100,000 miles per second.

Caudal

Relating to the tail.

Cause

That which brings about something else (an effect). Professor Adam Leroy Jones says: “It has been objected that we can never observe one thing producing another; that we can at most observe that one thing is followed by another, and perhaps find reason for believing that it will always have such connection; and that to say that A produces B, is to raise a metaphysical question with which science and everyday thinking are not concerned. Is it sufficient to say that cause means simply invariable connection? No, for the succession of day and night is an invariable succession. The notion of cause implies that the relation of cause and effect not only is invariable, but also that it must be so; that there is an unconditional or necessary connection between the two; that if the first does not happen, the second cannot. A causal law is a statement, in general terms, of a causal connection.”.

Cell

A battery unit, a device for changing chemical energy into electricity. The structural unit of which living beings are composed. An enclosed cavity in an organism or a mineral. A covering which protects the eggs or the young of certain animals.

Celsius

Centigrade (thermometer).

Cenogetic

Pertaining to individual development which does not repeat the development of the group of which the individual is a member.

Cenozoic

Relating to the geological age of the mammals. It is still in existence.

Center of gravity

The point in a body where its entire weight may be assumed to be concentrated.

Centigrade

A thermometer, or the scale on which it is based, with the boiling point of water at 100 and the freezing point at zero, under standard conditions of pressure. Abbreviation: C. Such a scale is far more useful to scientists than that of Fahrenheit.

Centimeter

One hundredth of a meter.

Centrifugal

Flying or tending to fly away from the center.

Centripetal

Tending to move toward the center.

Centrosome

A minute body found in the cytoplasm or the nucleus of some (biological) cells.

Centrum

The center of an earthquake.

Cephalic

Relating to the head.

Cephalopoda

The highest class of mollusks.

Cereal

A grass which produces edible grain.

Cerium

A metallic element. Symbol: Ce.

Cetacea

The order of mammals including the whales.

Chemistry

The science which deals with the composition of matter and its transformations.

Chiroptera

An order containing the bats.

Chloride

A chlorine compound.

Chlorine

A gaseous element. Symbol: Cl.

Chlorophyll

The coloring-matter of green parts of plants.

Chromatic aberration

The colored fringe seen at the edges of images formed by a simple lens, because of the difference in wave lengths of the various rays.

Chromium

A metallic element. Symbol: Cr.

Chromo-

Color-, in many compounds. Also: chroma-, chromato-.

Chromosome

One of the small bodies formed out of a protoplasmic substance (chromatin) in the nucleus before a cell divides.

Civilization

An advanced stage of culture. Civilization is sometimes contrasted with culture, but the matter is one which cannot be considered here.

Class

A group of animals or plants, more comprehensive than an order and less so than a phylum.

Climate

The average weather conditions of a particular place or region.

Cobalt

A metallic element. Symbol: Co.

Coccus

A spherical bacterium. A sort of carpel.

Coelenterata

A phylum of invertebrate animals including the corals.

Cohesion

Molecular attraction within a body.

Colloid

Not crystalloid. A substance which does not form a true solution. Colloidal liquids have very little osmotic pressure.

Columbium or Niobium

A metallic element. Symbol: Cb.

Combustion

Oxidation accompanied by the production of heat and light. Less frequently, the word is used for a combination which is not oxidation or where no heat or light is produced.

Common sense

Ordinary and non-scientific thought processes. Scientific thinking is more exact and more fertile.

Community

A social group.

Comparative

Involving comparison, as between man and the other animals.

Complex

In psycho-analysis, a cluster of ideas and mental images joined together by a stressed emotion; especially such a cluster that is thrust out of consciousness (repressed).

Component of a force

The effective value of a force in a given direction.

Compound animal, flower, leaf, etc

An animal, etc., consisting of a combination of organisms or simple parts.

Compound

A substance consisting of two or more chemical elements in combination.

Conation

Will, directing power, effort.

Concave

Curved like the interior of a circle or sphere.

Concept or Conception

The idea, notion, or thought held about anything. Conception includes symbol and meaning.

Condense

Change from gas to liquid. Concentrate (electricity). Of organic compounds, react in a certain way so as to form new bonds.

Conduct

Carry heat or electricity.

Conductance

Ability to conduct. The word is used to describe the property of a conductor.

Conductivity

Power to conduct (heat or electricity).

Conductor

That which readily conducts (heat or electricity).

Congeal

Solidify, freeze.

Connate

United from the beginning.

Constant

A quantity that does not vary, or one that does not change under given conditions.

Convex

Curved like the outside of a circle or sphere.

Copernican

Relating to the theory that the planets (one of which is the earth) move around the sun.

Copper

An important metallic element. Symbol: Cu.

Corolla

The inner envelope of a flower.

Corona

A small disk of light around the sun or moon. An appendage on top of a seed or the inner part of the corolla.

Cotyledon

One of the first leaves in the embryo of a higher flower.

Coulomb

The amount of electricity carried in one second by one ampere.

Coördinate

Each of a system of magnitudes used to fix the position of a point, line, or plane.

Cretaceous

Of or like chalk. Relating to the last Mesozoic period.

Cri

The common respiratory infections, such as the common cold, influenza, etc.

Criminology

The scientific study of crime and criminals.

Cross-pollination

The transfer of pollen from the anthers of one flower to the stigma of another flower of the same kind.

Crustacea

A class of hard-shelled arthropods, including lobsters and crabs.

Crystal

An aggregation of molecules with definite internal structure and external form of a solid enclosed by symmetrically arranged plane faces. A crystal is formed when certain liquids or gases solidify (crystallize). The study of crystal structure is crystallography.

Ctenophora

A class of low animals comprising certain jellyfish.

Cycle

A series of operations in a heat engine. A two-cycle engine is one with a cycle of two strokes. Properly, it should be called a two-stroke-cycle engine.

Cyclone

A violent wind of low diameter. A circular wind system about an area of low pressure.

Cyst

A hollow organ containing a liquid secretion.

Cyto-

Cell-, in compounds.

Cytoplasm

Cell protoplasm, not including the nucleus.

Darwinism

Organic evolution in general. The theory that the origin of species is due to natural selection, as developed by Charles Robert Darwin. All biologists worthy of the name believe in evolution, but by no means all accept Darwinism in the narrow sense.

Declination

The angular distance of a heavenly body north or south of the celestial equator. The deviation of a magnetic needle from true north.

Decurrent

Extending downward, as the base of a leaf.

Dehydrate

Remove water, dry.

Dendrology

The scientific study of trees.

Devonian

Of the geological formation between the Silurian and the Carboniferous.

Dew point

The temperature at which the air is saturated with water-vapor.

Diadelphous

Formed into two bundles. (Of stamens.).

Diandrous

With two stamens.

Dielectric

Insulating, insulator of electricity.

Diesel engine

An internal combustion motor which compresses the air highly and which successfully burns oil which is unsuitable for the ordinary motor of an automobile.

Disease

Malady. Of some foods and drinks, an impairment in quality caused by bacteria.

Dissipation of energy

The change of energy to such a form that it cannot be used to do work.

Dissociate

Ionize, decompose, split up.

Doldrums

A region of calms and light winds near the equator.

Dolichocephalic

Long-headed, having a skull with the breadth less than four-fifths of the length.

Drug

A medicine, a medicinal agent, especially one of vegetable origin.

Dynamics

The branch of physics dealing with forces.

Dyne

The amount of force that acts for a single second on a mass of one gram to give it a velocity of one centimeter per second.

Eccentric

Not concentric to a given circle. Arranged to change rotary motion back and forth.

Echinoderm

One of a class of animals including the sea-urchins.

Eclipse

Of a heavenly body, obscured by passing between it and the observer or its source of light.

Ecliptic

The apparent orbit of the sun.

Ecology

The science dealing with the relations between organisms and their environment.

Economics

The science of wealth, especially of its production, distribution, and consumption.

Edentate

Toothless or without canine teeth.

Effect

See Cause.

Efferent

Carrying outward or away.

Efficiency

The ratio between the amount of work put into a machine and the amount derived from it.

Efflorescence

The loss of water of crystallization.

Electricity

A peculiar condition of the molecules of a body or of the ether surrounding the molecules, or else a sort of fluid or other matter in the form of small bodies called electrons. It is easier to tell what electricity does or how it is produced than to define it, especially since physicists have not been able to agree about its precise nature.

Electrode

Either pole of a cell.

Electrolysis

The decomposition of a compound by means of an electric current.

Electrolyte

A substance which, in solution, can carry an electric current to an appreciable extent.

Electron

The electric charge of an atom. A very small particle which is electrically charged. The size of the electron has been variously calculated, and some physicists declare that the negative electron has only 1/1700 the mass of a hydrogen atom.

Element

One of a number of substances formerly considered to be indivisible. An electric cell.

Emanation

A gaseous substance produced by a radioactive material.

Embryo

The offspring of an animal before birth or emergence from the egg. The scientific study of the embryo is called embryology.

Endogenous

Growing from within.

Endosperm

The nutritive tissue enclosed with the embryo in seeds.

Endothelium

The layer of cells lining blood vessels, the interior of the heart, etc.

Energy

Ability to do work or change the nature of bodies. Heat and light are considered forms of energy.

Entomology

The study of insects.

Environment

Surrounding conditions, influences, and powers of all sorts. Everything which, directly or indirectly, affects the fate of an organism forms part of its environment.

Eocene

Relating to the lowest division of the Tertiary strata.

Epiphyte

A plant which grows upon another but which is not fed by it. A vegetable parasite on an animal body.

Equation

A compensation for inaccuracy. In mathematics, a formula affirming the equivalence of two expressions. An expression in symbols of a chemical reaction.

Equinox

The time when the sun crosses the equator, and day and night are of equal length.

Erbium

A metallic element. Symbol: Er.

Erg

The work done by a force that, when it acts for one second on mass of one gram, produces a velocity of one centimeter per second.

Erosion

Gradual destruction or wearing away, as of land by water.

Esthetics

Also spelled: æsthetics. The study of beauty. It is, at present, rather an art or a branch of philosophy than an exact science.

Ether

An anesthetic liquid. Totally distinct is this meaning: the medium through which light-waves pass, which is supposed to have a density infinitely less than that of the lightest gas. The nature of the ether is in dispute.

Ethics

The branch of philosophy concerned with human conduct. It may at some future time rank as a science.

Ethnology

The science dealing with the races of mankind. It has not, alas, always been thoroughly scientific.

Ethyl alcohol

The alcohol which cheers and also inebriates men. Before Prohibition, practically the only kind of alcohol which people drank.

Europium

A metallic element. Symbol: Eu.

Evaporate

Change (usually with no great rapidity) from the liquid to the gaseous state.

Evergreen

A tree or shrub which has green leaves in all seasons.

Evolution

Development, change. In biology, the development of a race or species by gradual change from another type. The Theory of Evolution contradicts the notion that every type was originally created in the form which it now has.

Experiment

An event (or, in the case of the verb: to bring about an event) designed for observation, in order that an unknown fact or principle may be brought to light, or simply to instruct.

Explain

To reduce a phenomenon to the terms of a general principle. To bring into a system.

Fact

Something which is true. If only a single investigator has reported a certain circumstance or condition, it is not likely to be considered a fact by scientists.

Factor

A substance which takes part in a chemical reaction.

Facula

A bright spot or streak on the sun.

Fahrenheit

A thermometric scale, in common household use, but employed for scientific purposes far less frequently than the Centigrade scale. The boiling point of water is 212 degrees and the freezing point is 32 degrees above zero.

Fair

As used by the American Weather Bureau, without rain, snow, or hail.

Feces

Excrement.

Fecundate

Impregnate, fertilize, make fruitful.

Female

Bearing fruit or offspring, pistillate.

Ferment

To cause an organic substance to change or to work (used of organic substances), because of the activity of yeast, or of certain other living organisms or substances derived from them.

Filament

The part of the stamen that supports the anther. The conductor in an incandescent electric light.

Fish

A member of a class of vertebrate and cold-blooded animals having gills and usually fins and scales.

Flocculus

A mass in the atmosphere of the sun resembling wool or clouds.

Florescence

The time or condition of flowering.

Flower

The reproductive organ in a plant which contains one or more pistils or stamens or both, and typically a corolla and calyx. To flower: to blossom or produce flowers.

Fluid

Moving readily. The fluids include the liquids, the gases, perhaps the ether of space.

Fluorescence

The colored light produced in some transparent bodies by the action of ultra-violet rays. The property some substances have of emitting light when exposed to certain rays.

Fluorine

A gaseous element. Symbol: F.

Focus

The point at which rays meet after reflection or refraction. Converging-point.

Force

That which changes or tends to change the motion of a body upon which it acts.

Foreconscious

Mental processes of which we are aware only under special conditions. Of a nature between conscious and unconscious.

Forensic

Used in law-courts.

Formula

A symbolic statement, as in mathematics or chemistry.

Fossil

Something left of an animal or a plant which lived in a former geological age.

Freeze

To change from a liquid to a solid, especially by removing heat.

Friction

The resistance which one body encounters in rubbing against another.

Fruit

A ripened ovary together with any parts of the flower that may be attached to it.

Fulcrum

The point where a lever is supported or turns.

Function

A quantity related to another in such a way that a change in one involves a change in the other.

Functional

Having a use. Of a disease, not affecting the structure of an organ, or of the organ which is supposed to be diseased. It is doubtful if there can be a disease which does not change the structure of some organ.

Fundamental notes

The notes resulting when a piano wire vibrates as a whole. The lowest notes of chords.

Fungus

Plural: fungi. A cryptogamous (flowerless) plant without chlorophyll. A morbid growth.

Fuse

To change, usually by adding heat, from solid to liquid form.

Gadolinium

A metallic element. Symbol: Gd.

Gallium

A metallic element. Symbol: Ga.

Gamete

A sexual cell which unites with another for reproduction.

Gamma rays

Becquerel rays which are more penetrating than beta rays and are not deflected by electricity. Equivalent or analogous to X-rays.

Ganglion

An enlargement of the nerve from which nerve-fibers radiate.

Gas

A fluid which tends to occupy the whole volume of any vessel in which it is placed.

Gastropoda

A class of mollusks including the snails.

Geld

Castrate.

Generalization

A universal assertion, a principle applying not to any single fact but rather to a large number. A general notion.

Genetics

The study of heredity and of the beginning of variation.

Genital

Pertaining to reproduction and the sexual organs.

Genus

In logic, a class which is divided into sub-classes. In biology, a class of animals usually containing several species. A single genus may in some cases make up a genus of its own, if it appears not to be closely related to any other genus. Plural: genera. The next higher group is the family.

Geo-

In combinations, earth-.

Geography

The study of the earth, especially as the environment of man.

Geology

The study of the crust of the earth.

Germ

A portion of an organism capable of becoming a new one. Seed, microörganism. Popularly, a germ is a bacterium which causes disease.

Germanium

A metallic element. Symbol: Ge.

Glacier

A slowly-moving mass of ice formed by the accumulation of snow on high ground.

Gland

An organ which secretes constituents of the blood. Secreting cell or cells in plants.

Glans

The body at the end of the penis and clitoris.

Glass

A substance made by mixing silicates and including some alkali silicate. Not every sort of glass is transparent.

Glomerate

Gathered in a compact group.

Glottis

The opening at the upper end of the windpipe.

Glucinum or Beryllium

A metallic element. Symbol: Gl or Be.

Glucose

One of a group of sugars, including grape sugar.

Gneiss

A sort of highly crystalline rock arranged in layers, as of quartz and mica.

Gold

A metallic element. Symbol: Au.

Gram

The unit of weight in the metric system. About the weight of a cubic centimeter of water at its greatest density.

Graph

A symbolical diagram, as in mathematics of chemistry.

Gravity or gravitation

The attraction existing between bodies. If the earth draws a falling apple, it is said that the apple also draws the earth to it.

Gregarious

Living in or pertaining to flocks, groups, or communities. Social.

Gymnosperm

A plant whose seeds are not enclosed in seed-vessels.

Habit

An action pattern; specifically, one that has been acquired. In biology, a mode of growth.

Hallucination

The perception of something which is not actually present.

Hardness

The presence of certain salts in water.

Heat

Energy which can be transmitted by conduction or radiation, and which is expressed in molecular motion.

Helium

A gaseous element. Symbol: He.

Henry

The unit of inductance. The inductance in a circuit in which the induced electromotive force is one volt when the inducing current varies at the rate of one ampere per second.

Herb

A plant whose stem is not woody or persistent.

Hermaphrodite

An organism possessing male and female characteristics or organs.

Herpetology

The study of reptiles.

Hexapoda

The order of insects.

Hilum

The point where the seed is attached to the seed-vessel.

Hinterland

The district behind a coast.

Histology

The study of organic tissues, usually with the aid of a microscope.

History

The study of the past. It deals with human institutions rather than with the animal, vegetable, or mineral kingdom. History is concerned first of all with concrete data, specific cases, and then with explaining them in the light of general laws. There have been some ingenious, but not altogether successful, attempts to make history into a science.

Holmium

A metallic element. Symbol: Ho.

Homo-

In compounds: same, similar.

Homology

That relation between parts which results from their development from corresponding embryonic parts, either in different animals or in the same individual.

Hormone

A stimulating substance carried from one organ to another.

Horse-power

The unit of power in the English system. It is equal to 550 foot pounds per second.

Humidity

Moisture.

Hurricane

A wind of stormy violence.

Hybrid

The offspring of two plants or animals of different sorts.

Hydrate

A compound containing combined water.

Hydraulics

The science dealing with liquids in motion.

Hydrocarbon

A compound of carbon and hydrogen.

Hydrogen

A gaseous element. Symbol: H.

Hydrolysis

The decomposition of water in such a reaction as includes the formation of new compounds with the hydrogen and the oxygen of the water.

Hydrometer

An instrument used to determine the specific gravity of a liquid.

Hydrostatics

The science which deals with the pressure of liquids.

Hydrous

Containing water, whether in combination or in a mixture.

Hydrozoan

A member of a class (Hydrozoa) of coelenterate animals, chiefly marine, including jellyfish.

Hygiene

The science of sanitation, preventive medicine. In the United States, textbooks of hygiene are chiefly concerned with proving that alcohol and tobacco are injurious. Here is an example of “science” created by legislative fiat.

Hygrometry

The measuring of atmospheric moisture.

Hypothesis

A supposition used as a basis for reasoning, a provisional explanation. If it appears to be unconfirmed by the facts, it is rejected. Otherwise it becomes a theory, then a law.

Igneous

Formed by great heat, as rocks.

Indehiscent

Not bursting open at maturity.

Indium

A metallic element. Symbol: In.

Indo-European or Indo-Germanic

Pertaining to a great family of languages including most of those spoken in Europe and by the white men in America as well as some used in India and other parts of Asia.

Inductance

The electrification of a conductor placed near a circuit or charged body, resulting from the proximity.

Inert

Not easily made to react.

Inertia

The property of matter by which it tends to remain at rest if it is at rest, or, if it is in motion, to remain in motion in a straight line. Our notion of inertia may possibly be changed by Einstein’s theory.

Inflorescence

Flowering, the arrangement of flowers on a plant.

Infra-

In compounds, below.

Infusoria

A class of protozoa which possess hairlike outgrowths.

Inorganic

Not derived from living organisms. Pertaining to the chemical compounds which do not contain carbon—but carbonates and a few other carbon compounds are considered to be inorganic.

Insect

A member of a class of small and invertebrate animals, all of which have bodies clearly divisible into head, thorax, and abdomen.

Instinct

An action pattern present from birth. (The varying theories of instinct, especially with regard to man, are often based upon varying definitions. This is true of many of the terms here defined.).

Intelligence quotient

The ratio between the “mental age” of an individual and the true age. The true age is often easier to determine than the mental age, that is, the age which a normal individual of a given intelligence possesses. How can intelligence be expressed numerically? Abbreviation: I. Q.

Interference

The influence which two waves have upon each other.

Invertebrate

Spineless, having no backbone.

Iodine

A solid, non-metallic element. Symbol: I.

Ion

Either of the substances that appear at the poles in electrolysis. Particle which carries electric charge. Positive ions are cations, negative ions are anions.

Iridium

A metallic element. Symbol: Ir.

Iron

An important metallic element. Symbol: Fe.

Isobar

A line connecting places which have the same barometric pressure (with corrections for varying altitude) at a given time or over a given period.

Isotherm

A line connecting places which have the same temperature at a given moment or over a stated period of time.

Joule

A unit of work. It is equal to ten million ergs, and it is about the energy expended in one second by an electric current of one ampere in a resistance of one ohm.

Jurassic

Of that Mesozoic period following the Triassic.

Kidney

One of a pair of organs which secrete urine.

Kilogram

A unit of mass in the metric system, about the mass of a cubic centimeter of water at its greatest density.

Kinetic theory of gases

The assumption and the teaching that the molecules of gases are constantly in motion and that the space between molecules is far greater than that occupied by the molecules themselves. The velocity of gas molecules is supposed to be very great.

Krypton

A gaseous element. Symbol: Kr.

Labile

Unstable.

Lanthanum

A metallic element. Symbol: La.

Latent heat

The equivalent of the work performed in changing the state of a substance from solid to liquid or liquid to gaseous.

Law

A generalization. A statement of the way things invariably behave under given conditions. A scientific law does not direct or impose penalties or state that things ought to behave in a certain way. It is a correct statement of invariable sequence. If the correctness of a statement has not been proved beyond a reasonable doubt, it is not a law.

Lead

A metallic element. Symbol: Pb.

Leaf

One of the expanded organs, usually green, springing from the stem, a branch, or sometimes a root, of a plant.

Lens

A portion of glass or other transparent substance with one or both sides curved, used to alter the direction of light rays.

Leucocyte

A colorless corpuscle of the blood.

Lever

A rigid structure used to modify force and motion while transmitting it.

Life

The quality which differentiates the organic from the inorganic. The ability to reproduce itself seems to be the differentiating characteristic of a living organism.

Light

A form of energy which is apprehended by the eye. It is supposed to move at a velocity of about 186,300 miles per second.

Limb

In astronomy, an edge or border. This is not the same word etymologically as the one which means an arm, a leg, or a wing.

Lithium

A metallic element. Symbol: Li.

Litmus

A substance which is turned red by acids and made blue again by bases. Paper stained with litmus is usually employed for such tests.

Logic

The science of thought. Scientific method.

Lutecium

A metallic element. Symbol: Lu.

Magnesium

A metallic element. Symbol: Mg.

Magnetize

To change into a magnet, give magnetic quality to, make capable of attracting iron.

Male

Of the sex or the organs that fecundate. Of a reproductive organ that fertilizes.

Mammal

One of the class of animals (Mammalia) which are vertebrate and which are distinguished by suckling their young.

Mandible

Jaw, especially the lower jaw. Part of a beak.

Manganese

A metallic element. Symbol: Mn.

Marsupial

One of an order of animals (Marsupialia) which are low mammals, and most of whose females carry the young in abdominal pouches.

Mass

Quantity of matter. This remains constant, but weight varies a little with geographical location.

Materia medica

The study of medicinal substances.

Mathematics

The science of space and quantity as such.

Matter

That which takes up space.

Mean

Equally removed from two extremes, average.

Mechanics

The science of motion. The study of the action of force on bodies. May be considered a branch of mathematics or of physics.

Medicine

The art of maintaining and restoring health. Surgery is sometimes excluded from the conception of medicine. The basis of medicine is only partially scientific.

Megacephalic

Large-headed.

Melt

To change from the solid to the liquid form.

Mendel’s Law

A principle formulated by Gregor Mendel with regard to the inheritance of characteristics. Fenton, following Walter, states it thus: “When two animals or plants unlike with respect to any character are crossed, the offspring of the first generation will be apparently like one of the parents in regard to the character in question. The parent which impresses its trait upon the offspring in this manner is called the dominant, while the one that fails to be visibly represented is the recessive. When, however, the hybrid progeny of this generation are in turn crossed with each other, they will produce a mixed lot of offspring, one-fourth of which will be like the dominant grandparent, one-fourth like the recessive one, and the remaining half like the parents which resembled the dominant grandparent, yet failed to breed true to it.”.

Mercury

Of the metallic elements, the only one which is ordinarily found in the liquid state. Quicksilver. Formula: Hg.

Mesozoic

Relating to the geological period between the Paleozoic and the Cenozoic.

Metabolism

The complete process of building up and breaking down protoplasm in a living organism. The process of digesting and storing nutritive matter and of excreting waste matter.

Metal

An element which replaces or is capable of replacing the hydrogen of an acid. One of a class of substances typically ductile, malleable, lustrous, translucent only through very thin layers, conducting heat and electricity well.

Metaphysics

The branch of philosophy dealing with knowing and being. This must disappear entirely as science advances.

Metazoa

All the complex animals. All the animals except the Protozoa.

Metric system

The decimal system of weights and measures generally used in many countries, employed for many purposes by scientists everywhere. A meter is about 1.094 yards. A kilometer is about .6214 of a mile. A cubic centimeter is about .061 of an inch. A kilogram is about 2.204 pounds. The C. G. S. (centimeter-gram-second) system is used in practically every science which deals with space, mass, and time.

Mho

A unit of electrical conductivity.

Micro-

Small, in many compounds.

Microbe

A very small organism; in popular use, a disease-producing bacterium, a germ.

Mineral

Pertaining to substances which are not organic. An ore.

Mineralogy

The science of ores.

Miocene

Relating to the middle division of the Tertiary (geological) period.

Mitosis

Cell division and multiplication by the usual process.

Mixture

A mass of more than one sort of material which is not chemically compounded or united.

Molecule

The smallest amount of a substance which can exist with the properties belonging to the substance.

Molybdenum

A metallic element. Symbol: Mo.

Momentum

The quantity of motion of a moving body. It is equal to the mass multiplied by the velocity.

Monadelphous

With the stamen filaments in a single bundle.

Monecious

Hermaphrodite. Having male and female flowers on the same plant.

Moniliform

Jointed in such a way as to resemble a necklace.

Monopoly

Sufficient control to influence price.

Monotreme

One of the lowest order (Monotremata) of mammals.

Monsoon

A periodic wind. Specifically, such a wind in the Indian Ocean.

Moraine

The mass of earth and other matter deposited by a glacier.

Morphology

The study of form (of organisms or of words).

Motor

Pertaining to a nerve and an impulse causing motion. Relating to action and the consciousness of action. Pertaining to a muscle causing action. A machine which causes motion, especially such an electric machine or one which is comparatively small.

Muscle

A fibrous band or bundle which contracts to produce movement in an animal body.

Muscology

The study of mosses.

Mutation

A sudden variation which may produce a new species.

Mycology

The study of fungi.

Myriapoda

A class of arthropods including the centipedes.

Narcotic

A substance which induces sleepiness.

Nascent

Just beginning, having special properties because of just having been released from combination.

Neap tide

The tide at which the high water mark is the lowest.

Nebular Hypothesis

The hypothesis advanced by Laplace that (in the words of F. W. Dyson) “a vast nebula—diffused tenuous matter—once extended to the confines of the solar system, and under the influence of gravitation slowly contracted. As the contraction proceeded the rotation necessarily increased, and rings or other masses were thrown off which collected and formed planets.” Any of several more or less similar hypotheses.

Nectar

A sweet fluid produced by plants.

Neocene

Relating to the later part of the Tertiary (geological) period.

Neodymium

A metallic element. Symbol: Nd.

Neolithic

Relating to the later part of the Stone Age.

Neon

A gaseous element. Symbol: Ne.

Nerve

The rib of a leaf. A vein. One of the fibers or bundles of fibers carrying impulses of sensation and motion.

Neurosis

Activity of the nerves. A functional disease attributed to the nerves.

Neutral

Neither acid nor basic in reaction. Without sex organs.

Nickel

A metallic element. Symbol: Ni.

Niton

A gaseous element which occurs in radium emanation. Symbol: Nt.

Nitrogen

A gaseous element constituting about four-fifths of the air. Symbol: N.

Noble metals

Metals which do not oxidize in air or oxygen. Among the noble metals are gold, silver, and platinum.

Node

A knob or root or branch, where a leaf is usually borne. One of the points where the orbit of a planet or comet and the ecliptic meet. A point or line which is at rest in a vibrating body.

Normal

Conforming to a standard or type. The normal is not necessarily superior to the abnormal.

Nutritive

Of value as food.

Ohm

An electrical unit of resistance. The resistance of a circuit in which one volt produces one ampere of current.

Oligocene

Of the Tertiary (geological) period, between the Eocene and Miocene.

Ontogeny

Individual development.

Opsonic

Causing bacteria to be consumed more readily by phagocytes.

Optics

The science of light and vision.

Optimum

The environment most favorable to the growth of a plant or animal.

Ordovician

Relating to the Paleozoic (geological) period between the Silurian and the Cambrian.

Ore

A native mineral from which a metal or metals may be extracted.

Organic

Living, or derived from a living organism. Relating to all the carbon compounds except a few simple ones. Relating to an organ. Affecting the structure of an organ—of a disease, opposed to functional.

Organism

An organized being, plant or animal. A living individual.

Osmium

A metallic element. Symbol: Os.

Ovary

The part of the pistil which contains rudimentary seeds. One of the two reproductive organs in which eggs are produced.

Overtone

A tone produced by secondary vibrations, as of segments of a piano wire.

Ovum

An egg or female germ. Plural: ova.

Oxidize

Combine with oxygen.

Oxygen

An important gaseous element. Symbol: O. About one-fifth of the air is oxygen.

Paleo-

In many combinations, old, ancient. Also: palæo-, palaeo-.

Paleontology

The science dealing with life in former geological periods, with species now extinct but made manifest by fossil remains.

Paleozoic

Of the oldest geological periods. More usually, of the era between the Mesozoic and the Pre-cambrian. The words designating geological eras have been used differently by various scientists.

Palladium

A metallic element of the platinum group. Symbol: Pd.

Parallax

The apparent displacement of an object caused by the actual change in the position of the observer, or by the assumption of two different points of observation. The parallax is expressed in degrees of an angle.

Paralogy

Mental illness.

Parasite

A plant or animal that derives nourishment or shelter from another upon which, with which, or within which it lives.

Parthenogenesis

Reproduction without the union of male and female.

Pascal’s Law

The law formulated by Pascal which is fundamental for the mechanics of fluids: A fluid under pressure exerts equal force upon equal areas of surface.

Pelagian or Pelagic

Relating to the open sea. Pelagic organisms are those which do not approach the shore.

Penology

The study of punishment for crime. If this science were studied scientifically, perhaps it would cease to exist.

Perennial

Lasting for several years; specifically, lasting for more than two years.

Phagocyte

A leucocyte which consumes disease-producing organisms.

Phase

The aspect of the moon or of a planet depending on the amount of illumination. Position of variation with regard to a real or assumed starting-point. An individual chemical in a mixture.

Phenomenon

Probably more familiar in the plural: phenomena. Something which is perceived by the senses. An event of scientific interest.

Philology

The science of language. The philologists have been inclined recently to extend their science, so that it deals with meaning, with folklore or traditional beliefs, and with various other subjects which are more or less closely related to language.

Philosophy

Literally: the love of wisdom. Former: the sum of knowledge, a complete system of knowledge, sometimes with emphasis upon its use in regulating human conduct. Philosophy is now primarily ethical. Durant insists that the growth of the various sciences makes it all the more necessary to be concerned with philosophy, which directs the proper use of knowledge. Religion, incidentally, is concerned chiefly with the field indicated for philosophy, not with the ground covered by the various sciences.

Phonology

The study of sounds in speech.

Phosphorus

A non-metallic element. Symbol: P.

Photics or Photology

The science of light.

Photo-

In compounds, light or photographic.

Phyllo-

In compounds, leaf. For instance, Phyllopoda: an order of crustaceans with feet resembling leaves.

Phylo-

In compounds, tribe, race. As, phylogeny: racial development, the natural history of a type.

Phylum

One of the largest divisions of animals or plants.

Physics

The science of matter and energy, not including fields which are considered chemical or biological.

Pistil

The female organ of a flower, including style, stigma, and ovary.

Planet

One of the bodies which revolve about the sun, including the earth but not comets or meteors.

Plant

A living organism which is not an animal. One which does not have sensation or voluntary motion. (This definition must be revised in the light of recent investigations.) Specifically, one of the smaller plants, excluding trees and shrubs.

Platinum

A metallic element. Symbol: Pt.

Pleistocene

Of the geological epoch before the Recent, in the Quaternary period of the Cenozoic era.

Pole

One of the two points in the celestial sphere about which the stars seem to revolve. One of the extremities of the axis of the earth. One of the points on a magnet where magnetic force is manifested. The anode or the cathode of a cell. The extremity of an axis of a spherical or oval cell or organ.

Politics

The science of government. Popularly, the art of exploiting democratic citizens, as practiced by office-holders and those who control them.

Pollen

The substance discharged from a flower, fertilizing or male grains.

Pollination

The carrying of pollen to the pistils.

Polonium

A substance found in pitchblende, perhaps an element.

Poly-

In compounds, many-. For example, polyadelphous: having the stamens united in three or more bundles. Polyandrous: having at one time more than one husband. Polygynous: having at one time more than one wife.

Postglacial

Belonging to a later period than that of the glaciers. Recent.

Potassium

A metallic element. Symbol: K.

Potential energy

Energy which is latent, not employed or in motion. Energy which a body has because of its position.

Poundal

The force which can act upon a pound mass for a second to give it a velocity of one foot per second, or which will give a mass of one pound an acceleration of one foot per second each second.

Practice

What is true in theory works out in practice, all due allowances for the influence of other theoretic laws having been made.

Praseodymium

A metallic element which occurs in rare minerals. Symbol: Pr.

Pre-Cambrian

Relating to the geological eras before the Cambrian period.

Precipitate

To change into liquid form. To cause a substance to be deposited in solid form from a solution. To make a dissolved substance insoluble. That which has been precipitated.

Prehensile

Used for grasping, suitable for grasping.

Pressure

The amount of exertion of force, expressed by the weight upon a unit area.

Primate

A member of the highest order (Primates) of mammals, including man and the monkeys.

Property

That which belongs to a whole class but is not used to distinguish it from others. Characteristic. A legal right to wealth.

Protean

Variable, readily changing form.

Proteid

Protein, or member of a special class of proteins.

Protein

One of a class of complex organic substances consisting of carbon, hydrogen, nitrogen, oxygen, and, in some cases, other elements. All living cells contain proteins.

Protoplasm

The living matter of which all animal and plant cells are formed.

Protozoan

A member of the phylum (Protozoa) of animals of the simplest type. A one-celled animal.

Pseudo-

In many compounds, false, seeming, similar to.

Psychiatry

The treatment of mental disease.

Psychical research

The study of phenomena which are not considered by scientists as realities, and which are explained by some persons as due not to natural forces but rather to spirit as opposed to matter. If such phenomena are explained by means of the laws of physics and psychology, there is no need for special “psychical research.” There seems to be no reason why we should postulate spiritual or vital force, even if our knowledge is not yet sufficient to explain all phenomena scientifically.

Psychology

The study of the mind; in practice, the study of behavior. Literally: the science of the soul. Perhaps psychology is not yet a true science, but this branch of knowledge is undoubtedly becoming more scientific, in spite of strong philosophical and mystical tendencies.

Psychophysics

The study of the relation between the mental and the physical, between psychology and physics.

Psychosis

Mental derangement, especially when there is no apparent brain or nerve injury. Consciousness, a conscious process.

Pteridophyte

One of a phylum (Pteridophyta) of flowerless plants, including the ferns.

Pure

Unmixed, abstract. Pure science deals with general principles, not with particular applications.

Pyro-

In compounds, fire-, fever-.

Quantel

An elementary entity of matter consisting of positive and negative parts, moving in all directions with the velocity of light, capable of passing through solids. (According to the theory of Langmuir.).

Quantity

Anything which can be represented by means of a number. In chemistry, the number of gram molecules.

Quantum

The unit of energy transmitted by radioactive bodies.

Quaternary

Belonging to the most recent geological period.

Radical

Pertaining to a root, growing out of or from a point close to the root. An atomic group which remains unchanged during the ordinary reactions of the compound of which it is a part.

Radicle

That part of the embryo of a plant which develops into the main root. A rootlike subdivision of a nerve or vein. Sometimes a mere spelling variation of radical.

Radioactive

Emitting invisible rays that penetrate opaque matter and produce electrical effects. Radium and some other substances are especially radioactive, but radioactivity is supposed to be characteristic of all substances.

Radium

A metallic element. Symbol: Ra.

Rarefaction

Making less dense.

Ray

A line at right angles to the wave front in which various forms of energy may be transmitted.

React

Tend in the reverse direction, enter into chemical combination. Act because of a stimulus.

Reaction

An opposing force. A chemical change. The usual nervous response.

Real number

A number representing a quantity and one of two opposite directions or senses.

Recapitulation Theory

The theory which was at one time generally favored by evolutionists, still accepted by many biologists, that ontogeny recapitulates phylogeny; i. e., that the development of the individual is an abridgement of the natural history of the species to which it belongs.

Recent

In geology, pertaining to the epoch still in existence.

Rectify

Purify, as by repeated distillation. (Important in the chemistry of bootlegging.).

Reduce

Remove oxygen, which combines with another substance.

Refract

Deflect (light, for example) at an angle. Refraction is due to varying velocity in two mediums.

Relativity

Dependence of one quantity or knowledge upon another. The Theory of Relativity formulated by Albert Einstein, based upon the principle that the universe is a four-dimensional (time-space) continuum, includes the conclusions that there is no absolute length, that unobstructed light rays have a constant velocity irrespective of the relative velocity between the observer and the source of light, that the velocity of matter can never reach the velocity of light unless the matter becomes light, that the mass of a body depends on its velocity.

Reproduction

Generation, the process of creating offspring of about the same kind as the parents. Apparently the power of reproduction is that which chiefly sets apart the living from the non-living. However, the fact that an individual organism is incapable of reproducing or taking part in reproduction does not show that it is dead.

Reptile

One of a class (Reptilia) of animals including snakes and crocodiles. The Reptilia are vertebrate animals which breathe air.

Resistance

Non-conductivity, opposition.

Rheo-

Stream, Current-, in compounds, chiefly electrical terms. As rheostat: a device for regulating current by controlling resistance.

Rhizo-

Root-, in compounds. As, rhizopod: one of a class (Rhizopoda) of protozoa having psuedopodia (“false feet”) which resemble roots.

Rhodium

A metallic element. Symbol: Rh.

Rodent

One of an order (Rodentia) of mammals, including rats, rabbits, squirrels, and other gnawing animals.

Root

A part of a plant, not necessarily but usually growing underground, which attaches it to supporting points and conveys nourishment.

Rubidium

A metallic element. Symbol: Rb.

Ruminant

One of a division (Ruminantia) of cud-chewing or at least herbivorous mammals with hooves.

Ruthenium

A metallic element. Symbol: Ru.

Réaumur

A thermometric scale with the boiling point of water at 80 degrees and the freezing point at zero.

Röntgen rays or X-rays

Forms of radiation produced when cathode rays strike the walls of the tube or the surface of a body placed within the tube.

Salt

A compound in which all or part of the hydrogen of an acid has been replaced by a metal, or by some other inorganic element or radical. Common salt is one of the general class of salts, and it is known to chemists as sodium chloride.

Samarium

A metallic element. Symbol: Sm.

Saponify

To turn a fat or oil into soap by combining it with an alkali. The term also includes a wider range of reactions in which hydrolysis is involved.

Saturate

To cause a substance to combine with or to absorb the greatest possible amount of another substance. To neutralize.

Scandium

A metallic element. Symbol: Sc.

Science

Exact, organized, and usually generalized knowledge. A special scientific field or system. Specifically, physical or natural science, not including philology or sociology. It is best not to attach too much importance to such a distinction. See also Art and Common sense.

Secondary

In geology, Mesozoic. Relating to reactions or compounds considered less important or less simple than those which are called primary. Of later origin. Induced. Relating to a second part.

Selenium

A solid, non-metallic element. Symbol: Se.

Semen

The generative fluid of a male animal.

Seminal

Relating to seed, semen, reproduction, or germs.

Seminiferous

Carrying seed or semen.

Sensation

The consciousness of perceiving or seeming to perceive a bodily state or an external object.

Sentiment

An emotionally-colored tendency or attitude.

Sepal

A segment of the calyx of a flower.

Septum

A partition, as between two hollow chambers of an organism.

Sessile

Attached directly by the base.

Sex

The condition of being male or female or both.

Sheath

Membrane, tissue, skin, or other tight-fitting cover.

Shrub

A woody plant smaller than a tree. A bush.

Silicon

A non-metallic element, solid in ordinary temperatures. The compounds are extremely common. Symbol: Si.

Silver

A metallic element. Symbol: Ag.

Simoom

A hot, dry wind of western Asia.

Simple

Not compound. Consisting of a single cell, element, or individual. Not divided or branched.

Social psychology

The study of the behavior of human groups. Incidentally, social psychology is an easier subject than individual psychology for the investigator. Where is the man who has never been influenced by other human beings?.

Social

Living in groups or as a part of a complex organism. Working together. Relating to society.

Sociology

The science of society. The study of the development of social institutions. As sociology exists now, it is scientific only in small parts.

Sodium

A metallic element. The compounds are common, including ordinary table salt (sodium chloride). Symbol: Na.

Soil

A fine earthy matter on the surface, in which plants can grow.

Solid

Relating to the condition of matter in which it has a stable shape and volume, with some elasticity.

Solution

A mixture of substances which is the same throughout the mass. We think chiefly of the solution of solids or gases in liquids, but solutions entirely of gases are common, and of solids within solids are possible.

Somatic

Relating to the body as a whole or to that part from which no new individuals are developed.

Sound

Vibrations produced when some object is set in motion, causing a stimulation of the organs and nerve centers of hearing.

Species

A group subordinate in classification to the genus. The members of a species differ only in minor details. In logic, a class may be a species one time and a genus another. In biology, the classes remain fixed. Homo sapiens, the class which embraces all mankind, is always a species.

Specific gravity

The ratio between the weight of a given amount of a substance and the weight of the same amount of a standard substance, usually water at the temperature where it is densest. For gases, there are various standards.

Spectroheliograph

An instrument for photographing the sun by daylight.

Spectrum

The image formed by rays of light which are separated into their component wave-lengths. Less frequently, the phenomenon (not entirely visual) produced when other forms of radiant energy are thus split up.

Sperm

Semen.

Spermary

The organ where semen develops.

Spore

A minute organic body that develops into a new individual. A single cell that becomes free and develops independently.

Sporozoan

One of a class (Sporozoa) of parasitic protozoans which reproduce by means of spores.

Sport

A sudden and striking deviation from type. A mutation.

Stable equilibrium

Such a condition in a body that, if suspended like a pendulum and pushed to one side, it resumes its original position immediately below the point of suspension.

Stamen

The male (pollen-bearing) organ of a plant.

Star

A heavenly body. More usually, those that appear to be fixed dots of light, including the sun but not the planets or meteors, are included in the term. One of the “fixed” stars. The stars are either named or numbered in various catalogues.

State

Condition, especially the being in solid, liquid, or gaseous form. An organized political community.

Statics

The study of bodies at rest and forces in equilibrium; a branch of mechanics. According to Einstein, no body is ever at rest.

Statistics

The systematic collection of numerical facts. The study which deals with collection of this sort and with the interpretation of statistics in the first sense.

Stigma

The part of the style or ovary-surface that receives pollen. A small speck or mark.

Stipule

A small appendage to a leaf.

Stratum

In geology, a layer or set of layers of rock or earth. In biology, a layer of tissue.

Strontium

A metallic element. Symbol: Sr.

Style

A narrowed extension of the ovary which supports the stigma.

Subalpine

Living or growing just below the alpine zone.

Sublimation

The direct change from the solid to the gaseous state.

Sulphur

A solid non-metallic element. Symbol: S. It occurs native and in many compounds.

Superstition

Irrational fear of or credulity about the unknown. To the ignorant person, almost everything is unknown. Particular forms of superstition are transmitted from generation to generation and from group to group. Superstitions which masquerade as science are not unknown.

Symbol

A letter, word, or other thing which represents an object or quantity or idea. The symbol is frequently an abbreviation. In chemistry, it is the Latin name of the element which is abbreviated to form the symbol.

Synclinal

Dipping toward a common line or point.

Synthetic

Produced outside the living organism. Artificial. Making more complex.

Tantalum

A metallic element. Symbol: Ta.

Tellurium

A rare non-metallic element. Symbol: Te.

Temperature

Degree, not total amount, of heat.

Tendon

A cord or band of tissue connecting a muscle with another part.

Terbium

A metallic element. Symbol: Tb.

Tertiary

Relating to the third in a series, as of organic compounds. Relating to the geological period before the Quaternary.

Thallium

A metallic element. Symbol: Tl.

Thallophyte

One of a phylum (Thallophyta) of simple plants including fungi and lichens.

Thallus

A simple plant body without root, stem, or leaves.

Theology

The “science” of religion, especially Christian religion, and of God, according to lexicographers and other writers. Newman argues very well that if there is a miracle-working God whom we can understand by studying the Bible and the traditions of the Catholic Church, then theology is an essential branch of science. I do not see how any man who grants his premises can fail to agree with him.

Theory

A generalization which has not been absolutely proved. Sometimes one that stands between a hypothesis and a law, not so certain as the latter, more certain than the former. However, phrases continue, often when their meaning has changed, and it seems that “Theory of Evolution” may be used when the Fundamentalists have already accepted it. Also scientific principles in general. Sound theory and proper practice are not enemies.

Thermo-

In compounds, heat, temperature. As, thermodynamics: the science of the relation between heat and mechanical work.

Thorax

The part of the trunk between the neck and the tail or the abdomen.

Tin

A metallic element. Symbol: Sn. Most objects which we say, in ordinary language, are made of tin, are made of tin plate.

Tincture

The alcoholic solution of a drug.

Titanium

A metallic element. Symbol: Ti.

Triassic

Relating to the geological division between the Permian and the Jurassic.

Typhoon

A violent hurricane.

Ulotrichi

The wooly-haired races of mankind.

Ultra-violet rays

Invisible rays of the spectrum beyond the violet rays.

Ungulate

One of a group (Ungulata) of mammals having horns and hoofs.

Uranium

A metallic element. Symbol: U. Uranium is radioactive.

Vacuum

A space which does not contain matter. A vacuum, in a laboratory, is a space which has been exhausted of matter to a great extent; for scientists have not been able to produce a perfect vacuum.

Value

The amount of other commodities for which a thing can be exchanged in the open market.

Valve

The membranous part of an organ which permits the flow of a liquid in one direction only.

Vanadium

A metallic element. Symbol: V.

Vapor

A gas, especially one which exists at ordinary temperatures in liquid or solid form.

Velocity

Rate of motion.

Vertebrate

Having a spinal column, belonging to the class of Vertebrata.

Vitalism

The theory that there is a special force in living beings, distinct from the ordinary physical and chemical forces. Few scientists are vitalists, although many preachers are, and a number of philosophers as well.

Vitamines

Organic substances found in various foods and apparently necessary to human life. Their exact chemical constitution remains unknown.

Volt

The unit of electromotive force. The pressure which produces a current of one ampere when applied to a conductor with a resistance of one ohm.

Volume

The space a body occupies.

Wave

A disturbance of the particles of a fluid medium as in the transmission of sound, heat, and light.

Weight

The force with which the earth attracts a body. See Mass.

Work

The expenditure of force in overcoming force or producing a molecular change. Futile efforts do not constitute work.

X-Ray

See Röntgen ray.

Xenon

A gaseous element. Symbol: X.

Xylogy

The study of the structure of wood.

Yttrium

A metallic element. Symbol: Y or Yt.

Zinc

A metallic element. Symbol: Zn.

Zirconium

A metallic element. Symbol: Zr.

Zoöchemistry

The study of the constituents of animal bodies.

Zoölogy

The science of animals.

Zygote

A cell formed by the joining of a male and a female cell, capable of developing into a new individual.

Zymosis

Fermentation.

Zymurgy

The chemistry of fermentation processes.