theory

theory (http://definr.com/theory)

     n 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 theory about 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" [syn: hypothesis, possibility]
     3: a belief that can guide behavior; "the architect has a
        theory that more is less"; "they killed him on the theory
        that dead men tell no tales"