axiom /ˈaksɪəm/ noun
a statement or proposition which is regarded as being established, accepted, or self-evidently true.
thesis /ˈθiːsɪs/ noun
a statement or theory that is put forward as a premise to be maintained or proved.
theory /ˈθɪəri/ noun
a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.