Noun
a theory of the structure of the atom
(chemistry) any theory in which all matter is composed of tiny discrete finite indivisible indestructible particles
Source: WordNetThe atomic theory was not generally accepted in the time of Democritus, largely because of its deterministic character, for it allows no chance, choice, or free will. John Freely
We catch a glimpse of the great river of science which never ceases to flow in India. For India has carried and scattered the data of intellectual progress for the whole world, ever since the pre-Buddhist period when she produced the Sankhya philosophy and the atomic theory. Kakuzo Okakura
The Atomic Theory and the Periodic Law have been given prominence, since their neglect unfailingly leads to obscurity and triviality. J. R. Partington
the ancient Greek philosophers Democritus and Epicurus held atomic theories of the universe Source: Internet
Despite the uncertainty at the heart of Dalton's atomic theory, the principles of the theory survived. Source: Internet
Dalton found that an atomic theory of matter could elegantly explain this common pattern in chemistry. Source: Internet