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
(particle physics) a theory that involves an eleven-dimensional universe in which the weak and strong forces and gravity are unified and to which all the string theories belong
based in theory rather than experiment
a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
