As a verb, postulate is usually defined as to ask, demand or claim. In other words: To claim or assume the existence or truth of, especially of a basis for reasoning or arguing.
As a noun, postulate is usually defined as something taken as self-evident or assumed without proof as a basis for reasoning. In other words, a proposition that requires no proof, being self-evident, or that is for a specific purpose assumed true, and this is used in the proof of other propositions, axioms.
