The Collaborative International Dictionary of English v.0.48:

Premise \Prem"ise\, n.; pl. Premises. [Written also, less
   properly, premiss.] [F. pr['e]misse, fr. L. praemissus, p.
   p. of praemittere to send before; prae before + mittere to
   send. See Mission.]
   1. A proposition antecedently supposed or proved; something
      previously stated or assumed as the basis of further
      argument; a condition; a supposition.
      [1913 Webster]

            The premises observed,
            Thy will by my performance shall be served. --Shak.
      [1913 Webster]

   2. (Logic) Either of the first two propositions of a
      syllogism, from which the conclusion is drawn.
      [1913 Webster]

   Note: "All sinners deserve punishment: A B is a sinner."
         [1913 Webster] These propositions, which are the
         premises, being true or admitted, the conclusion
         follows, that A B deserves punishment.
         [1913 Webster]

               While the premises stand firm, it is impossible
               to shake the conclusion.           --Dr. H. More.
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   3. pl. (Law) Matters previously stated or set forth; esp.,
      that part in the beginning of a deed, the office of which
      is to express the grantor and grantee, and the land or
      thing granted or conveyed, and all that precedes the
      habendum; the thing demised or granted.
      [1913 Webster]

   4. pl. A piece of real estate; a building and its adjuncts;
      as, to lease premises; to trespass on another's premises.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Premise \Pre*mise"\, v. t. [imp. & p. p. Premised; p. pr. &
   vb. n. Premising.] [From L. praemissus, p. p., or E.
   premise, n. See Premise, n.]
   1. To send before the time, or beforehand; hence, to cause to
      be before something else; to employ previously. [Obs.]
      [1913 Webster]

            The premised flames of the last day.  --Shak.
      [1913 Webster]

            If venesection and a cathartic be premised. --E.
                                                  Darwin.
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   2. To set forth beforehand, or as introductory to the main
      subject; to offer previously, as something to explain or
      aid in understanding what follows; especially, to lay down
      premises or first propositions, on which rest the
      subsequent reasonings.
      [1913 Webster]

            I premise these particulars that the reader may know
            that I enter upon it as a very ungrateful task.
                                                  --Addison.
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The Collaborative International Dictionary of English v.0.48:

Premise \Pre*mise"\, v. i.
   To make a premise; to set forth something as a premise.
   --Swift.
   [1913 Webster]

WordNet (r) 3.0 (2006):

premise
    n 1: a statement that is assumed to be true and from which a
         conclusion can be drawn; "on the assumption that he has
         been injured we can infer that he will not to play" [syn:
         premise, premiss, assumption]
    v 1: set forth beforehand, often as an explanation; "He premised
         these remarks so that his readers might understand"
    2: furnish with a preface or introduction; "She always precedes
       her lectures with a joke"; "He prefaced his lecture with a
       critical remark about the institution" [syn: precede,
       preface, premise, introduce]
    3: take something as preexisting and given [syn: premise,
       premiss]

Moby Thesaurus II by Grady Ward, 1.0:

119 Moby Thesaurus words for "premise":
   a priori principle, affirmation, ancestor, antecedent, apriorism,
   argue, assert, assertion, assume, assumed position, assumption,
   avant-propos, axiom, basis, basis for belief, body of evidence,
   breakthrough, categorical proposition, chain of evidence, clue,
   conjecture, data, datum, documentation, evidence, exhibit,
   exordium, fact, facts, first principles, forerunner, foreword,
   foundation, front matter, frontispiece, ground, grounds,
   grounds for belief, guesswork, hypothecate, hypothesis,
   hypothesis ad hoc, hypothesize, indication, inference, innovation,
   introduce, introduction, item of evidence, leap, lemma,
   major premise, manifestation, mark, material grounds,
   minor premise, muniments, mute witness, overture, philosopheme,
   philosophical proposition, piece of evidence, posit, position,
   postulate, postulation, postulatum, preamble, precedent, precursor,
   predicate, preface, prefix, prefixture, preliminary, prelude,
   premises, premiss, presume, presumption, presupposal, presuppose,
   presupposition, proem, prolegomena, prolegomenon, prolepsis,
   prologize, prologue, proof, proposal, propose, proposition,
   propositional function, protasis, put forth, reason to believe,
   relevant fact, set forth, set of postulates, sign, statement,
   sumption, supposal, suppose, supposing, supposition, surmise,
   symptom, theorem, theorize, thesis, token, truth table,
   truth-function, truth-value, verse, voluntary,
   working hypothesis