a. and sb. [f. ATOM + -IC. (Mod.L. atomicus, F. atomique.)]
A. adj.
1. Of or pertaining to atoms.
Atomic weight in Chem.: the weight of an atom of an element (or radical), as compared with that of an atom of hydrogen, which is taken as unity; also the sum of the weights of the atom of a compound; combining equivalent. Atomic volume of a body: the space occupied by a quantity of it proportional to its atomic or molecular weight.
1692. J. Edwards, Remark. Texts, 229. According to their hypothesis … this atomick bustle was from eternity.
1819. Children, Chem. Anal., 285. The. atomic composition of pyromucic acid.
1850. Daubeny, Atom. The., ix. 279. Supposing that all bodies were of the same specific gravity, the atomic weight of each would represent the relative size of its atoms, or in other words, its atomic volume.
2. About or concerned with atoms.
a. Atomic philosophy: the doctrine taught by Leucippus, Democritus and Epicurus: see ATOM sb. 1 and ATOMISM.
b. Atomic theory in Chem.: the doctrine that elemental bodies consist of aggregations of indivisible atoms of definite relative weight; that the atoms of different elements unite with each other in fixed proportions; and that the latter determine the fixed proportions in which elements and compounds enter into chemical combination with each other.
1678. Cudworth, Intell. Syst., Pref. 6. The Atomick Physiology … the foundation of the Democritick Fate.
1809. W. Irving, Knickerb. (1861), 7. The great atomic system taught by old Moschus … revived by Democritus of laughing memory; improved by Epicurus … and modernized by the fanciful Descartes.
1811. J. Dalton (title), Observations on Dr. Bostock’s Review of the Atomic principles of Chemistry.
1880. Cleminshaw, trans. Wurtz’ Atom. The., 26. From the year 1804 the atomic theory inspired all Dalton’s labours.
3. Of persons. Adhering to the atomic philosophy.
1691. Ray, Creation (1714), 41. These mechanick theists have quite outstripped … the atomick atheists.
1850. Daubeny, Atom. The., i. 46. That vantage ground which the atomic philosopher possesses over the rival theorist.
4. Atom-like in size; minute, tiny.
1809. Pearson, in Phil. Trans., XCIX. 319. These atomic globules are quite different.
1866. Rogers, Agric. & Prices, I. ii. 28. The means of measuring changes almost atomic.
5. Of the nature of atoms; simple, elemental.
1881. Lockyer, in Nature, No. 617. 391. Whether the temperature produces a simpler form, a more atomic condition of the same thing.
† B. sb. An adherent of the atomic philosophy.
1678. Cudworth, Intell. Syst., Pref. Other Philosophick Atheists … before those Atomicks, Epicurus and Democritus.
