Pos"tu*late (?), n. [L. postulatum a demand, request, prop. p. p. of postulare to demand, prob. a dim. of poscere to demand, prob. for porcscere; akin to G. forschen to search, investigate, Skr. prach to ask, and L. precari to pray: cf. F. postulat. See Pray.] 1. Something demanded or asserted; especially, a position or supposition assumed without proof, or one which is considered as self-evident; a truth to which assent may be demanded or challenged, without argument or evidence.

2. (Geom.) The enunciation of a self- evident problem, in distinction from an axiom, which is the enunciation of a self-evident theorem.

The distinction between a postulate and an axiom lies in this, -- that the latter is admitted to be self-evident, while the former may be agreed upon between two reasoners, and admitted by both, but not as proposition which it would be impossible to deny.

Pos"tu*late, a. Postulated. [Obs.] Hudibras.

Pos"tu*late (?), v. t. [imp. & p. p. Postulated (?); p. pr. & vb. n. Postulating.] 1. To beg, or assume without proof; as, to postulate conclusions.

2. To take without express consent; to assume.

The Byzantine emperors appear to have . . . postulated a sort of paramount supremacy over this nation.

3. To invite earnestly; to solicit. [Obs.] Bp. Burnet.

• To make claim for; to demand.
  
• To assume or assert the truth, reality, or necessity of, especially as a basis of an argument.
  
• To assume as a premise or axiom; to take for granted. See Synonyms at presume.
  
• Something assumed without proof as being self-evident or generally accepted, especially when used as a basis for an argument.
  
• A fundamental element; a basic principle.
  
• (logic) An axiom.
  
• A requirement; a prerequisite.