Forms: (4 attomus, athomus, 6–7 atomus), 5–7 attome, 6–7 attom, 6–8 atome, 7– atom. [a. F. atome, ad. L. atom-us ‘an atom’; also ‘the twinkling of an eye,’ a. Gr. ἄτομ-ος, subst. use of ἄτομ-ος, adj. ‘indivisible,’ f. ἀ priv. + -τομ-ος ‘cut,’ from strong stem of τέμ-ν-ειν to cut. In 16th c. chiefly used in the L. and Gr. forms atom-us, atom-os, with pl. atomi. About 1600 the F. form atome came into general use, and was at length anglicized to atom.]
I. In philosophical and scientific use.
1. A hypothetical body, so infinitely small as to be incapable of further division; and thus held to be one of the ultimate particles of matter, by the concourse of which, according to Leucippus and Democritus, the universe was formed.
1477. Norton, Ord. Alch. (in Ashm. 1652), v. 79. Resolving in Attomes [the 15th c. form is uncertain: the MSS. (16th and 17th cc.) have attomis, atomes, attoms, anotamies.]
1546. Langley, Pol. Verg. De Invent., I. ii. 4 b. Epicurus one of Democritus dysciples putteth two Causes Atomos or motes and Vacuitie or Emptinesse; of these he saith the foure Elementes come.
1603. Holland, Plutarch’s Mor., 807. Epicurus saith: That the principles of all things be certeine Atomes.
1606. Bryskett, Civ. Life, 170. Epicures opinion … that the falling of his motes or Atomi should breed necessitie in our actions.
1709. Swift, Trit. Ess., Wks. 1755, II. I. 139. That the universe was formed by a fortuitous concourse of atoms.
1837. Whewell, Hist. Induct. Sc. (1857), I. 48. The technical term, Atom, marks sufficiently the nature of the opinion. According to this theory, the world consists of a collection of simple particles, of one kind of matter, and of indivisible smallness … and by the various configurations and motions of these particles, all kinds of matter and all material phenomena are produced.
2. In Nat. Phil. Physical Atoms: the supposed ultimate particles in which matter actually exists (without reference to their divisibility or the contrary), aggregates of which held in their places by molecular forces, constitute all material bodies.
1650. Charleton, Paradoxes, Prol. 14. The imperceptible Emissions, streaming in a semi-immaterial thread of Atomes from sublunary bodies.
1777. Priestley, Matt. & Spir., i. (1782), I. 11. By an atom … I mean an ultimate component part of any gross body.
1871. Tyndall, Fragm. Sc., I. ii. 35. Atoms are endowed with powers of mutual attraction.
3. Chemical Atoms: a. The smallest particles in which the elements combine either with themselves, or with each other, and thus the smallest quantity of matter known to possess the properties of a particular element.
1819. Children, Chem. Anal., 437. The composition of hyposulphuric acid must be, 2 atoms of sulphur, 5 of oxygen.
1868. Chambers, Encycl., I. 527. What the chemist regards as an atom in his science, may not be an ultimate and indivisible atom in a physical point of view; the chemical atom, though incapable of division as a chemical atom, may still be composed or built up of many physical atoms.
1873. Williamson, Chem., § 85. Each atom of oxygen in water is combined with two atoms of hydrogen.
b. The smallest quantity in which a group of elements, called a radical, forms a compound corresponding to one formed by a simple element, or behaves like an element; thus the smallest known quantity of a chemical compound.
1847. Nat. Encycl., III. 395. The Benzoyle atom is formed of twenty-one elementary atoms—C14 H5 O2.
1873. Williamson, Chem., § 84. N H4 is a radical analogous to potassium, and N H4 is capable in many compounds of taking the place of K. N H4 is called an atom of ammonium.
II. In popular use.
4. From sense 1, as the nearest popular conception to the atoms of the philosophers: One of the particles of dust which are rendered visible by light; a mote in the sunbeam. arch. or Obs.
1605. Z. Jones, De Loyer’s Specters, 27. Atomes signifie motes in the Sunne.
1627. Drayton, Aginc. (1631), 61. Bils and Axes play As doe the Attoms in the Sunny ray.
1784. Cowper, Task, I. 361. The rustling straw sends up a frequent mist Of atoms.
1821. Byron, Two Fosc., III. i. Moted rays of light Peopled with dusty atoms.
5. The smallest conceivable portion or fragment of anything; a very minute portion or quantity, a particle, a jot: a. of matter.
c. 1630. Drumm. of Hawth., Poems (1633), 166. Like tinder when flints atoms on it fall.
1644. Digby, Nat. Bodies, vi. (1658), 54. Little attoms of oyl … ascend apace up the week of a burning candle.
1835. Sir J. Ross, N. W. Pass., xxxiv. 477. There was not an atom of water.
b. of things immaterial.
c. 1630. Drumm. of Hawth., Poems (1656), 136. We as but in Mirrour see, Shadows of shadows, Atomes of thy Might.
1651. Hobbes, Leviath., III. xliii. 331. Casting atomes or Scripture, as dust before mens eyes.
1866. G. Macdonald, Ann. Q. Neighb., i. 2. I do not feel one atom older than I did at three and twenty.
c. esp. in To smash, shiver, etc., to or into atoms.
1664. H. More, Myst. Iniq., 495. They would nimbly take a-pieces and consume to Atomes any such Terrestrial consistency of flesh and bloud.
1705. Otway, Orphan, V. vii. 2114. If but your word can shake This World to Atomes.
1874. Helps, Soc. Press., iii. 51. Which should shiver into atoms some of our present most potent ideas.
6. A very minute or microscopic object (without implying that it is a particle of anything else); anything relatively very small; an atomy.
1633. Herbert, Ch. Milit., in Temple, 184. The smallest ant or atome knows thy power.
1664. Power, Exp. Philos., I. 26. Her eyes are two such very little black Atoms.
1884. Roe, in Harper’s Mag., March, 616/1. A saucy little atom of a bird.
b. attrib.
1742. Young, Nt. Th., IV. 421. And shall an atom of this atom-world Mutter, in dust and sin, the theme of heaven?
1813. L. Hunt, in Examiner, 15 Feb., 104/1. The swarm Of atom bees.
III. Of time. (Already in Gr. ἄτομος (1 Cor. xv. 22), L. atomus = ‘twinkling of an eye,’ and regularly fixed in value in med.L.; see Du Cange.)
† 7. The smallest mediæval measure of time; = 15/94 of a second. Obs.
According to the table of Papias in Du Cange—
| 47 atoms of time | = 1 ounce | = 71/2 seconds | (modern) | |
| 8 ounces | = 1 ostent | = 1 minute | ” | |
| 11/2 ostents | = 1 moment | = 11/2 minutes | ” | |
| 22/3 moments | = 1 part | = 4 minutes | ” | |
| 11/2 parts (or 4 moments) | = 1 minute | = 6 minutes | ” | |
| 2 minutes | = 1 point | = 12 minutes | ” | |
| 5 points | = 1 hour | = 1 hour | ” |
1398. Trevisa, Barth. De P. R., IX. ix. (1495), 354. An vnce of tyme conteynyth seuen and forty attomos. Ibid., xxi. 359. Dyuydynge … of tyme passyth no ferder than Athomus.
IV. Comb. a. attrib., as atom-dance; b. instrumental, as atom-born. Atom-theory: the theory that accounts for the properties of bodies by the shape, position, etc., of their atoms.
1878. Geo. Eliot, Coll. Breakf. Party, 191. You saw the facial atom-dance.
1819. Shelley, Ode to Heaven, 485. The abyss is wreathed with scorn At your presumption, atom-born.
1871. R. H. Hutton, Ess., I. 40. Why do scientific men attach … less and less [credit] to the atom-theory of matter?
