1.Definition: 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"

Category: General

2.Definition: 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"

Related Noun(s):hypothesis, possibility

Category: General

3.Definition: 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"

Category: General