an ancient philosophical theory, developed by Democritus and expounded by Lucretius, that the ultimate constituents of the universe are atoms
atom (sense 3)
2.
a.
any of a number of theories that hold that some objects or phenomena can be explained as constructed out of a small number of distinct types of simple indivisible entities
b.
any theory that holds that an understanding of the parts is logically prior to an understanding of the whole
Compare holism (sense 3)
3. psychology
the theory that experiences and mental states are composed of elementary units
Derived forms
atomist (ˈatomist)
noun, adjective
atomistic (ˌatomˈistic) or atomistical (ˌatomˈistical)
adjective
atomistically (ˌatomˈistically)
adverb
atomism in American English
(ˈætəmˌɪzəm)
noun
Philosophy
a theory that the universe is made up of tiny, simple, indivisible particles that cannot be destroyed