noun \ˈthē-ə-rē, ˈthi(-ə)r-ē\
plural the·o·ries

Definition of THEORY

: the general or abstract principles of a body of fact, a science, or an art <the theory and practice of medicine>
: a plausible or scientifically acceptable general principle or body of principles offered to explain natural phenomena <a theory of organic evolution>—see atomic theory, cell theory, germ theory
: a working hypothesis that is considered probable based on experimental evidence or factual or conceptual analysis and is accepted as a basis for experimentation
the·o·ret·i·cal \ˌthē-ə-ˈret-i-kəl, ˌthi(ə)r-ˈet-\ also the·o·ret·ic \-ik\ adjective
the·o·ret·i·cal·ly \-i-k(ə-)lē\ adverb

Seen & Heard

What made you want to look up theory? Please tell us where you read or heard it (including the quote, if possible).