English
atom
Atom comes from Latin atomus ‘smallest particle’, from Ancient Greek ἄτομος ‘indivisible’, and ultimately from Proto-Indo-European *temh₁- ‘to cut’.
- Proto-Indo-Europeanc. 4500–2500 BCE*temh₁-1‘to cut’reconstructed
- Proto-Indo-Europeanc. 4500–2500 BCE*tm̥-né-h₁-ti1reconstructed
- Ancient Greekc. 800–300 BCEτέμνω2‘to cut’
- Ancient Greekc. 800–300 BCEἄτομος2átomos‘indivisible’
- Latinc. 75 BCE–200 CEatomus2‘smallest particle’
- Middle Frenchc. 1400–1600athome2
- Middle Englishc. 1150–1500attome2
- Englishearliest quotation 1835atom2
attested reconstructed ? uncertain or disputed deepest recorded ancestor
- 1 Wiktionary, Ancient Greek τέμνω
- 2 Wiktionary, English atom
- Earliest quotation in Wiktionary’s entry: 1835, John Ross, James Clark Ross: “Towards the following morning, the thermometer fell to 5°;…”.
Lineage
- Proto-Indo-Europeanc. 4500–2500 BCE*temh₁-Wiktionary, Ancient Greek τέμνω‘to cut’reconstructed
- Proto-Indo-Europeanc. 4500–2500 BCE*tm̥-né-h₁-tiWiktionary, Ancient Greek τέμνωreconstructed
- Ancient Greekc. 800–300 BCEτέμνωWiktionary, English atom‘to cut’
- Ancient Greekc. 800–300 BCEἄτομοςWiktionary, English atomátomos‘indivisible’
- Latinc. 75 BCE–200 CEatomusWiktionary, English atom‘smallest particle’
- Middle Frenchc. 1400–1600athomeWiktionary, English atom
- Middle Englishc. 1150–1500attomeWiktionary, English atom
- Englishearliest quotation 1835atomWiktionary, English atom. Earliest quotation in Wiktionary’s entry: 1835, John Ross, James Clark Ross: “Towards the following morning, the thermometer fell to 5°;…”
The story
Atoms are so named because they were historically thought up as to be the smallest unit of matter, and thus indivisible.
Word family
English words that share an ancestor with atom, grouped by the ancestor they share, most familiar first.
through Proto-Indo-European *temh₁- ‘to cut’
- contempt ← contemptus ← contemnō ← temnō ← *tm̥-ne-h₁-ti
- templar ← templer ← templier
- tempestuous ← tempestious ← tempestous ← tempestuōsus ← tempestās
through Ancient Greek τέμνω ‘to cut’
- epitome ← ἐπιτομή ← ἐπιτέμνω
- tome ← tomus ← τόμος
- dichotomous ← dichotomos ← διχότομος
- toma ← tome ← tomus ← τόμος
66 more relatives in the full family tree
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Today it means
noun The smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons.
Sources
Sources: Wiktionary, “atom”; the older steps come from the Wiktionary entry for Ancient Greek τέμνω. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.
Etymograph / Proto-Indo-European *temh₁- / atom