1. A well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena
   "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory"
    
2. A tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
   "a scientific hypothesis that survives experimental testing becomes a scientific theory"; "he proposed a fresh theory of alkalis that later was accepted in chemical practices"; "a scientific possibility that survives experimental testing becomes a scientific theory";
   - hypothesis, possibility
    
3. A belief that can guide behaviour
   "the architect has a theory that more is less"; "they killed him on the theory that dead men tell no tales"

Derived forms: theories

Type of: belief, concept, conception, construct, explanation

Encyclopedia: Theory, Culture and Society