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atom

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Pronunciation

Etymology

It is inherited from Middle English attome, also athomus.[2][3] The OED explains it as partly borrowed from Latin atomus (“indivisible particle, atom”), in the earliest forms, and partly borrowed from Middle French athome or atome, recorded in Old French from the second half of the 13th century.[4][3][5] The Latin word, used especially by Lucretius,[6][3] comes from Ancient Greek ἄτομος (átomos), the noun use of the adjective meaning "uncut, indivisible",[4][6][7][8] formed from ἀ- (a-, “not”) and the stem of τέμνω (témnō, “to cut”),[1][8][9] from Proto-Indo-European *tem- (“to cut”).[6][9] The same Latin word gave Spanish átomo (1348), Portuguese átomo and Italian atomo (late 14th century).[4] The Greek base *tom-, "cut", is also the source of anatomy and tome.[10][8]

Earliest recorded meaning

In Old English, in Byrhtferth's Enchiridion, the word named the smallest unit of time used in the Middle Ages, of which there were 376 in a minute and 22,560 in an hour; the same text also has it for an indivisible thing.[4][11][10] The Middle English Dictionary's first quotations, from Trevisa's translation of Bartholomaeus (before 1398), are of the same unit of time.[2]

Semantic evolution

Already in Greek and Latin the word could mean a brief moment, the twinkling of an eye, as well as a particle that cannot be divided,[4][5] and Klein notes that the Greek philosopher Leucippus first used it of such particles.[8] Barnhart adds that Democritus developed this atomic philosophy and Lucretius carried it into Latin.[3] In English the philosophical sense, a minute indivisible particle of matter, is first found in Thomas Norton's Ordinal of Alchemy (about 1477),[4][3] while from 1555 the word was used of the particles of which matter is made, without reference to the Greek thinkers.[4][11] Johnson (1755) defined it as "such a small particle as cannot be physically divided".[12] Figurative uses followed: a mote of dust in a sunbeam (1588), the smallest fragment of something, as in blown to atoms (1610), the smallest bit of something immaterial (1626) and a tiny person or thing (1633, in George Herbert).[4] The British chemist John Dalton gave the word its scientific sense in his atomic theory of 1805,[3][13][6] and the OED's first chemical use is from his New System of Chemical Philosophy (1810).[4] Word Origins notes that Ernest Rutherford disproved the idea that the atom cannot be divided when he split it in 1919.[14] From 1945 the atom stood for nuclear energy and nuclear weapons,[4] and atom bomb is recorded in The Times of 7 August 1945.[14][6] A verb atom, to break into atoms, was used from 1648 to 1779.[4][11]

Timeline

  • Old English – the smallest medieval unit of time; an indivisible thing.[4][11]
  • before 1398 – attomos, of the unit of time, in Trevisa.[2]
  • c. 1477 – a particle of ancient atomic philosophy, in Norton's Ordinal of Alchemy.[4][3]
  • 1555 – each of the particles of which matter is composed.[4][11]
  • 1588 – a mote of dust in a sunbeam.[4]
  • 1610 – the smallest particle of a substance.[4]
  • 1626 – the smallest quantity of something immaterial, a jot.[4][11]
  • 1633 – a very small thing or person.[4]
  • 1648–1779 – verb, to reduce to atoms.[4]
  • 1805 – Dalton's atomic theory.[3][6]
  • 1810 – the chemical sense.[4]
  • 1945 – the atom as a source of nuclear energy, and atom bomb.[4][6][14]

Modern meaning

Noun

  1. The smallest unit of a chemical element that can take part in a chemical reaction, made of a nucleus surrounded by electrons: Each water molecule holds one atom of oxygen.
  2. This unit as the source of nuclear energy: an age that tried to tame the atom.
  3. (history) The hypothetical indivisible particle that some ancient philosophers took to be the basic stuff of matter.
  4. Any unit regarded as the indivisible building block of a theory or system.
  5. A very small amount; a jot: There was not an atom of doubt in her voice.
  6. (history) The smallest medieval unit of time.

Word family

  • atomic
  • atomism
  • atomistic
  • atomize
  • subatom
  • atom bomb

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
  3. ^ a b c d e f g h Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  4. ^ a b c d e f g h i j k l m n o p q r s t u Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  5. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
  6. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  7. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  8. ^ a b c d Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  9. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
  10. ^ a b Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
  11. ^ a b c d e f Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)
  12. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
  13. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
  14. ^ a b c Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press