The Collaborative International Dictionary of English v.0.48:

Mistake \Mis*take"\, v. i.
   To err in knowledge, perception, opinion, or judgment; to
   commit an unintentional error.
   [1913 Webster]

         Servants mistake, and sometimes occasion
         misunderstanding among friends.          --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mistake \Mis*take"\ (m[i^]s*t[=a]k"), n.
   1. An apprehending wrongly; a misconception; a
      misunderstanding; a fault in opinion or judgment; an
      unintentional error of conduct.
      [1913 Webster]

            Infallibility is an absolute security of the
            understanding from all possibility of mistake.
                                                  --Tillotson.
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   2. (Law) Misconception, error, which when non-negligent may
      be ground for rescinding a contract, or for refusing to
      perform it.
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   No mistake, surely; without fail; as, it will happen at the
      appointed time, and no mistake. [Low]
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   Syn: Blunder; error; bull. See Blunder.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mistake \Mis*take"\ (m[i^]s*t[=a]k"), v. t. [imp. & obs. p. p.
   Mistook (m[i^]s*t[oo^]k"); p. p. Mistaken
   (m[i^]s*t[=a]k"'n); p. pr. & vb. n. Mistaking.] [Pref. mis-
   + take: cf. Icel. mistaka.]
   1. To take or choose wrongly. [Obs. or R.] --Shak.
      [1913 Webster]

   2. To take in a wrong sense; to misunderstand misapprehend,
      or misconceive; as, to mistake a remark; to mistake one's
      meaning. --Locke.
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            My father's purposes have been mistook. --Shak.
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   3. To substitute in thought or perception; as, to mistake one
      person for another.
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            A man may mistake the love of virtue for the
            practice of it.                       --Johnson.
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   4. To have a wrong idea of in respect of character,
      qualities, etc.; to misjudge.
      [1913 Webster]

            Mistake me not so much,
            To think my poverty is treacherous.   --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mistake
    n 1: a wrong action attributable to bad judgment or ignorance or
         inattention; "he made a bad mistake"; "she was quick to
         point out my errors"; "I could understand his English in
         spite of his grammatical faults" [syn: mistake, error,
         fault]
    2: an understanding of something that is not correct; "he wasn't
       going to admit his mistake"; "make no mistake about his
       intentions"; "there must be some misunderstanding--I don't
       have a sister" [syn: mistake, misunderstanding,
       misapprehension]
    3: part of a statement that is not correct; "the book was full
       of errors" [syn: error, mistake]
    v 1: identify incorrectly; "Don't mistake her for her twin
         sister" [syn: mistake, misidentify]
    2: to make a mistake or be incorrect [syn: err, mistake,
       slip]

Moby Thesaurus II by Grady Ward, 1.0:

97 Moby Thesaurus words for "mistake":
   bad job, bevue, bloomer, blooper, blunder, bobble, boggle,
   bonehead play, boner, boo-boo, boob, botch, bungle, clanger,
   clerical error, clumsy performance, contort, corrigendum, distort,
   erratum, error, etourderie, failure, false step, fault, faute,
   faux pas, flub, fluff, foozle, fumble, gaffe, garble, gaucherie,
   get one wrong, get wrong, gloss, goof, hash, howler, human error,
   indiscretion, make a miscue, make a mistake, mess, misapply,
   misapprehend, misapprehension, miscalculation, miscarriage,
   miscite, misconceive, misconception, misconstrue, miscount, miscue,
   misdeal, misdeem, misexplain, misexplicate, misexpound,
   misidentification, misidentify, misinterpret, misjudge,
   misjudgment, misplay, misprint, misquotation, misquote, misread,
   misrender, misreport, miss, misstatement, misstep, mistranslate,
   misunderstand, misunderstanding, misuse, muff, near-miss, off day,
   pervert, sad work, slip, slipup, squeeze, strain the sense,
   stumble, take for, torture, trip, twist the words, typo,
   typographical error, wrench



Bouvier's Law Dictionary, Revised 6th Ed (1856):

MISTAKE, contracts. An error committed in relation to some matter of fact
affecting the rights of one of the parties to a contract.
     2. Mistakes in making a contract are distinguished ordinarily into,
first, mistakes as to the motive; secondly, mistakes as to the person, with
whom the contract is made; thirdly, as to the subject matter of the
contract; and, lastly, mistakes of fact and of law. See Story, Eq. Jur. Sec.
110; Bouv. Inst. Index, h.t.; Ignorance; Motive.
     3. In general, courts of equity will correct and rectify all mistakes
in deeds and contracts founded on good consideration. 1 Ves. 317; 2 Atk.
203; Mitf. Pl. 116; 4 Vin. Ab. 277; 13 Vin. Ab. 41; 18 E. Com. Law Reps. 14;
8 Com. Digest, 75; Madd. Ch. Prac. Index, h.t.; 1 Story on Eq. ch. 5, p.
121; Jeremy's Eq. Jurisd. B. 3, part 2, p. 358. See article Surprise.
     4. As to mistakes in the names of legatees, see 1 Rop. Leg. 131; Domat,
l. 4, t. 2, s. 1, n. 22. As to mistakes made in practice, and as to the
propriety or impropriety of taking advantage of them, see Chitt. Pr. Index,
h.t. As to mistakes of law in relation to contracts, see 23 Am. Jur. 146 to
166.