The Collaborative International Dictionary of English v.0.48:

Postulate \Pos"tu*late\, a.
   Postulated. [Obs.] --Hudibras.
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The Collaborative International Dictionary of English v.0.48:

Postulate \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.
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   2. To take without express consent; to assume.
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            The Byzantine emperors appear to have . . .
            postulated a sort of paramount supremacy over this
            nation.                               --W. Tooke.
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   3. To invite earnestly; to solicit. [Obs.] --Bp. Burnet.
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The Collaborative International Dictionary of English v.0.48:

Postulate \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.
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   2. (Geom.) The enunciation of a self-evident problem, in
      distinction from an axiom, which is the enunciation of a
      self-evident theorem.
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            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.
                                                  --Eng. Cyc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

postulate
    n 1: (logic) a proposition that is accepted as true in order to
         provide a basis for logical reasoning [syn: postulate,
         posit]
    v 1: maintain or assert; "He contended that Communism had no
         future" [syn: contend, postulate]
    2: take as a given; assume as a postulate or axiom; "He posited
       three basic laws of nature" [syn: postulate, posit]
    3: require as useful, just, or proper; "It takes nerve to do
       what she did"; "success usually requires hard work"; "This
       job asks a lot of patience and skill"; "This position demands
       a lot of personal sacrifice"; "This dinner calls for a
       spectacular dessert"; "This intervention does not postulate a
       patient's consent" [syn: necessitate, ask, postulate,
       need, require, take, involve, call for, demand]
       [ant: eliminate, obviate, rid of]