The Collaborative International Dictionary of English v.0.48:

Postulate \Pos"tu*late\, a.
   Postulated. [Obs.] --Hudibras.
   [1913 Webster]

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.
      [1913 Webster]

   2. To take without express consent; to assume.
      [1913 Webster]

            The Byzantine emperors appear to have . . .
            postulated a sort of paramount supremacy over this
            nation.                               --W. Tooke.
      [1913 Webster]

   3. To invite earnestly; to solicit. [Obs.] --Bp. Burnet.
      [1913 Webster]

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.
      [1913 Webster]

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

            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]

Moby Thesaurus II by Grady Ward, 1.0:

191 Moby Thesaurus words for "postulate":
   a priori principle, a priori truth, absolute fact, accepted fact,
   actual fact, admitted fact, advance, affirm, affirmation,
   apriorism, assert, assertion, assume, assumed position, assumption,
   avant-propos, aver, axiom, bald fact, bare fact, basis,
   breakthrough, bring before, bring forward, bring up, broach,
   brocard, brutal fact, call, categorical proposition, center,
   challenge, circumstance, claim, cold fact, commend to attention,
   conceded fact, conjecture, core, data, datum, demonstrable fact,
   dictate, dictum, elixir, empirical fact, essence, essential,
   established fact, exact, exordium, fact, fact of experience,
   first principles, flower, focus, foreword, formula, foundation,
   front matter, frontispiece, fundamental, gist, given fact,
   golden rule, gravamen, ground, guesswork, hard fact, heart,
   hypostasis, hypothesis, hypothesis ad hoc, indisputable fact,
   inescapable fact, inference, inner essence, innovation, introduce,
   introduction, kernel, launch, law, lay before, lay down, leap,
   lemma, major premise, make a motion, marrow, matter of fact, meat,
   minor premise, moot, move, naked fact, not guesswork, not opinion,
   nub, nucleus, nuts and bolts, offer a resolution, open up,
   overture, philosopheme, philosophical proposition, pith, plain,
   pose, posit, position, positive fact, postulation, postulatum,
   preamble, predicate, preface, prefer, prefix, prefixture,
   preliminary, prelude, premise, presume, presumption, presupposal,
   presupposition, principium, principle, proem, prolegomena,
   prolegomenon, prolepsis, prologue, propose, proposition,
   propositional function, propound, protasis, provable fact,
   put forth, put forward, put it to, quid, quiddity, quintessence,
   recommend, require, requisition, rule, salient fact, sap,
   self-evident fact, self-evident truth, set before, set forth,
   set of postulates, settled principle, significant fact,
   simple fact, sober fact, solicit, soul, spirit, start, statement,
   stubborn fact, stuff, submit, substance, suggest, sumption,
   supposal, supposing, supposition, surmise, the case,
   the nitty-gritty, theorem, thesis, truism, truth, truth table,
   truth-function, truth-value, undeniable fact, universal truth,
   verse, voluntary, well-known fact, working hypothesis