Main Entry: the·o·ry

Pronunciation: \ˈthē-ə-rē, ˈthir-ē\

Function: noun

Inflected Form(s): plural the·o·ries

Etymology: Late Latin theoria, from Greek theōria, from theōrein

Date: 1592

1 : the analysis of a set of facts in their relation to one another
2 : abstract thought : speculation
3 : the general or abstract principles of a body of fact, a science, or an art <music theory>
4 a : a belief, policy, or procedure proposed or followed as the basis of action <her method is based on the theory that all children want to learn> b : an ideal or hypothetical set of facts, principles, or circumstances —often used in the phrase in theory <in theory, we have always advocated freedom for all>
5 : a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena <the wave theory of light>
6 a : a hypothesis assumed for the sake of argument or investigation b : an unproved assumption : conjecture c : a body of theorems presenting a concise systematic view of a subject <theory of equations>

synonyms see hypothesis