molecule

Etymology

It is borrowed from French molécule, recorded in French from 1674,^[2][3][4] from New Latin molecula,^[2][3][5][6] a diminutive of Latin mōlēs (“mass, barrier”),^[3][4][5] the source of mole in the sense of a breakwater, formed with -cula, English -cule.^[2][4][7] The OED finds the Latin word in Gassendi, before 1655, and thinks it arose in the debates started by Descartes's physical theories;^[2][8] Etymonline likewise traces the vogue for the word to Descartes.^[4]

Earliest recorded meaning

One of the tiny particles of which matter was thought to be made: the OED's first quotation is from the Philosophical Transactions of the Royal Society, 1701.^[2][9] Barnhart and Etymonline date the English form to 1794, and Barnhart finds the Latin molecula, with the Latin plural -ae, used in English contexts from 1678.^[3][4]

Semantic evolution

At first the word was vague, any minute particle,^[4] and until the late 18th century it was used mostly in its Latin form.^[4][3] The modern scientific sense, the smallest part of a substance that keeps its chemical character, goes back to Amedeo Avogadro's use of the Latin word in 1811.^[4][7] In 19th-century chemistry it was also used for an equivalent quantity of a substance, a gram-molecule (1867–78), and in biology for a tiny particle of tissue (1826–51), both obsolete.^[2] The general sense, a very small particle, dates from 1799, and the figurative use for the smallest unit of something, such as a person in a community, from 1839.^[2] The adjective molecular followed in 1823.^[3]

Timeline

• 1674 – French molécule.^[2][3]
• 1678 – the Latin molecula in English contexts.^[3]
• 1701 – one of the minute particles of which matter is made.^[2][9]
• 1794 – molecule, an extremely minute particle.^[4][3]
• 1799 – any very small particle.^[2]
• 1811 – Avogadro uses molecula in the modern scientific sense.^[4][7]
• 1823 – the adjective molecular.^[3]
• 1839 – the smallest unit of something; an individual in a community.^[2]

Meanings

Noun

1. The smallest unit of a chemical compound or element that keeps its chemical identity, made of one or more atoms held together by chemical bonds: a molecule of water.^[10][9][2]
2. A very small particle; a tiny bit.^[10][2]

Word family

• biomolecule
• submolecule
• supermolecule
• gram molecule

Related words

• molecular
• mole
• -cule

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g h i j Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ a b c d e f g h i j Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
6. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
9. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
10. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins