Molecule definitions and example sentences on Wordnik

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Definitions (15)

American Heritage Dictionary (2)

noun The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces.
noun A small particle; a tiny bit.

Century Dictionary (10)

The smallest mass of any substance which is capable of existing in a separate form — that is, the smallest part into which the substance can be divided without destroying its chemical character (identity). All the physical changes of a body, as the dissolving of sugar in water, the melting of lead, the change of water into steam, the magnetization of steel, and so on, are phenomena which take place without the loss of identity of the substance itself, and which concern the relations of the molecules among themselves. Hence the molecule is taken as the physical unit. A homogeneous body is regarded as made up of similar molecules, whose relations determine its physical qualities, and particularly its physical state as a gas, liquid, or solid. A gas, according to the kinetic theory of gases, is composed of molecules darting about in paths which are very nearly rectilinear through the greater part of their lengths. Liquids are supposed to be composed of molecules which wander about, but have not nearly rectilinear paths; while solids are believed to be composed of molecules bound together by cohesion and moving in quasi-orbital paths. A molecule of any substance is conceived as made up of one or more atoms, whose relations to each other are considered in chemistry. (See atom.) The exact nature of the molecules is still largely a matter of hypothesis, but as regards their size Sir William Thomson has reached a quasi-definite conclusion as follows: “If a drop of water were magnified to the size of the earth, the molecules or granules would each occupy spaces greater than those filled by small shot and smaller than those occupied by cricket-balls.” A molecule may consist of several distinct portions of matter held together by chemical bonds. So long as the different portions do not part company, but travel together in the excursions made by the molecule, our theory calls the whole connected mass a single molecule. Clerk Maxwell, Heat, p. 286. The molecule of any substance is, by some chemists, defined as being the smallest portion of that substance to which can be attributed all the chemical properties of the substance; by others, as the smallest portion which, so long as the substance is chemically unchanged, keeps together without complete separation of its parts. Encyc. Brit., XVI. 611. We have, I believe, what we may almost call a new chemistry, some day to be revealed to us by means of photographic records of the behaviour of molecules. J. N. Lockyer, Spect. Anal., p. 109.
A very small particle or bit of something; a particle; an atom. [Colloquial]
In ornithology, the tread or cicatricula of a fecundated ovum. [Rare.]

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But just ask what the molecule -- how should it fold up? — James Watson on how he discovered DNA
It was pretty obvious that it provided the information to an RNA molecule, and then how do you go from RNA to protein? — James Watson on how he discovered DNA
The left-hand part of the molecule is identical in every single species of bacteria. — Bonnie Bassler on how bacteria "talk"
But the right-hand part of the molecule is a little bit different in every single species. — Bonnie Bassler on how bacteria "talk"
I know this molecule was a tour-de-force effort by the mil. — The Explosives and Weapons Forum: medina?

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atom · protein · compound · concentration · component · ion · cell · substance · structure · gene · crystal · receptors

Roget's II: The New Thesaurus, Third Edition by the Editors of the American Heritage® Dictionary. Copyright © 2003, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Etymologies (2)

American Heritage Dictionary (1)

French molécule, from New Latin mōlēcula, diminutive of Latin mōlēs, mass.

Century Dictionary (1)

from French molécule = Spanish molécula = Portuguese molecula = Italian molecula, molecola, from New Latin molecula, a molecule, diminutive of Latin moles, a mass: see mole.

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