/thee"euh ree, thear"ee/ , n. , pl. theories .
1. a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein's theory of relativity.
2. a proposed explanation whose status is still conjectural, in contrast to well-established propositions that are regarded as reporting matters of actual fact.
3. Math. a body of principles, theorems, or the like, belonging to one subject: number theory.
4. the branch of a science or art that deals with its principles or methods, as distinguished from its practice: music theory.
5. a particular conception or view of something to be done or of the method of doing it; a system of rules or principles.
6. contemplation or speculation.
7. guess or conjecture.
[ 1590-1600; theoria theoría a viewing, contemplating, equiv. to theor ( eîn ) to view + -ia -Y 3 ]
Syn. 1. THEORY, HYPOTHESIS are used in non-technical contexts to mean an untested idea or opinion. A THEORY in technical use is a more or less verified or established explanation accounting for known facts or phenomena: the theory of relativity. A HYPOTHESIS is a conjecture put forth as a possible explanation of phenomena or relations, which serves as a basis of argument or experimentation to reach the truth: This idea is only a hypothesis.