LATIN DICTIONARYLexicon Latīnum
adjectivefirst/second-declension adjective

atomus1

atomus (feminine atoma, neuter atomum)
Classical[ˈa.tɔ.mʊs]Ecclesiastical[ˈaː.to.mus]

Meaning

  1. adjectiveindivisible

Declension

singular
formmasculinefeminineneuter
nominativeatomusatomaatomum
genitiveatomīatomaeatomī
dativeatomōatomaeatomō
accusativeatomumatomamatomum
ablativeatomōatomāatomō
vocativeatomeatomaatomum
plural
formmasculinefeminineneuter
nominativeatomīatomaeatoma
genitiveatomōrumatomārumatomōrum
dativeatomīsatomīsatomīs
accusativeatomōsatomāsatoma
ablativeatomīsatomīsatomīs
vocativeatomīatomaeatoma

ătŏmus, a, um, adj., = ἄτομος.
I. Uncut, not to be cut, indivisible: Graeci (tus) stagonian et atomum tali modo appellant, Plin. 12, 14, 32, § 62.—Far more freq.,
II. Subst.: ătŏmus (-ŏs), i, f., = ἡ ἄτομος, an indivisible element.
A. Of matter, an atom, of which particles, acc. to the doctrine of Democritus, all things are composed (the distinction between an atom, an ultimate particle of matter, and a molecule, the ultimate combination of matter, was of course unknown to the ancients; syn.: corpora, corpora parva, corpora minuta, corpuscula, Lucr., Cic.): atomi, id est corpora individua propter soliditatem, Cic. Fin. 1, 6, 17; id. Tusc. 1, 18, 42; id. N. D. 1, 20, 54; id. Fat. 11, 24; id. N. D. 1, 24, 66; id. Ac. 1, 2, 6 al.; Vitr. 2, 2; Lact. de Ira Dei, 10 (where, as in Vitr. 2, 2, acc. to several editt., it stands as masc.); Isid. Orig. 13, 2, 1 sqq.—
B. Of time: in atomo, after the Gr. ἐν ἀτόμῳ, in a moment, in the twinkling of an eye, Tert. Res. Carn. 42 and 51; id. adv. Marc. 3, 24; so in the Gr. Test. 1 Cor. 15, 52, but rendered in momento by the Vulg.

Origins

Borrowed from Ancient Greek ἄτομος (átomos, “uncut, indivisible”).

noun · femininesecond declension
atomus2
atomus f (genitive atomī)
Classical[ˈa.tɔ.mʊs]Ecclesiastical[ˈaː.to.mus]

Meaning

  1. femininean atom, particle incapable of being divided
  2. feminineinstant, moment (of time)

Declension

declension
formsingularplural
nominativeatomusatomī
atomoe
genitiveatomīatomōrum
dativeatomōatomīs
accusativeatomum
atomon
atomōs
ablativeatomōatomīs
vocativeatomeatomī
atomoe

Charlton Lewis's shorter dictionary for students: the same scholarship in plain, modern definitions.

atomus ī, f
, ἄτομος, an indivisible particle, atom.

Origins

Borrowed from Ancient Greek ἄτομος (átomos, “uncut, indivisible”).

Quick answers

What does atomus mean in Latin?
atomus, a adjective, means “indivisible”.
How do you pronounce atomus?
In classical Latin, [ˈa.tɔ.mʊs]; in ecclesiastical (church) Latin, [ˈaː.to.mus].