atomic theory

noun

1. Physics, Chemistry. any of several theories describing the structure, behavior, and other properties of the atom and its component parts.
2. Philosophy. atomism ( def 1 ).

atomic theory

noun

1. any theory in which matter is regarded as consisting of atoms, esp that proposed by John Dalton postulating that elements are composed of atoms that can combine in definite proportions to form compounds
2. the current concept of the atom as an entity with a definite structure See atomic structure

Word History and Origins

Origin of atomic theory¹

First recorded in 1840–50

Example Sentences

Manchester had been steadily attracting scientific prestige after John Dalton pioneered studies in atomic theory and colour blindness, while fellow student James Joule became a household name after his work in energy conservation.

From BBC

Thus, the atomic theory required that the universe be filled with emptiness—an infinite void.

From Literature

These fluids mix well together in outer portions of such a planet’s deep interior, but in the depths, the tenets of atomic theory predict they will “unmix” like water and oil.

From Scientific American

Scientific advances like X-rays and atomic theory seemed to reinforce the existence of a truth beyond appearances.

From New York Times

The progress in chemistry in the 19th century depended on the atomic theory.

From Scientific American