molecule

UK/ˈmɒl.ɪ.kjuːl/US/ˈmɑ.lɪ.kjul/

nounB1+Occasional — familiar, but not everyday · #9,182 of 15,258leans written

Other forms: molecules

A molecule is a group of atoms bonded together — the smallest piece of a substance that is still that substance. Two hydrogen atoms locked onto one oxygen atom make one molecule of water; pull them apart and you no longer have water.

The adjective is molecular: molecular biology, molecular weight, molecular structure. Molecules run from tiny to enormous — the oxygen you breathe is two atoms joined, while a DNA molecule holds millions, and chemists call the giants macromolecules. Keep three words straight. An atom is a single unit; a molecule is atoms bonded together; a compound is a substance whose molecules contain more than one element, so oxygen gas is a molecule but not a compound. And a molecule is not a speck: the dust floating in a sunbeam is a clump of billions of them.

Definitions of molecule

1nounmoleculeTwo or more atoms bonded together; the smallest unit of a substance that still behaves like that substance.B1+
“A water molecule is one oxygen atom joined to two hydrogen atoms.”

molecule is a unit of matter.

Where it comes from

Molecule came through French molécule from New Latin molecula, a diminutive of Latin moles, a mass. So a molecule is literally a little mass, a small lump. The name was chosen long before anyone could see one — a guess about smallness that turned out to be right.

French
molécule
English, today
molecule

Borrowed from French molécule. French molécule, from New Latin molecula (“a molecule”), diminutive of Latin moles (“a mass”).

Etymology from Wiktionary, CC BY-SA

Practised in Science & Space, Chemistry & Elements

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molecule in the wild

Diatomic molecules (from Greek di- 'two') are molecules composed of only two atoms, of the same or different chemical elements.
Diatomic molecule
In the kinetic theory of gases, the term molecule is often used for any gaseous particle regardless of its composition.
Molecule
Concepts similar to molecules have been discussed since ancient times, but modern investigation into the nature of molecules and their bonds began in the 17th century.
Molecule
The molecular mass (m) is the mass of a given molecule, often expressed in units of daltons (Da).
Molecular mass
Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element.
Molecular mass

From Wikipedia, CC BY-SA 4.0. These sentences were written by other people about their own subjects; they are here to show the word at work, not as anybody’s opinion.

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