Source : Webster's Revised Unabridged Dictionary (1913)

Laugh \Laugh\, v. i. [imp. & p. p. {Laughed}; p. pr. & vb. n.
   {Laughing}.] [OE. laughen, laghen, lauhen, AS. hlehhan,
   hlihhan, hlyhhan, hliehhan; akin to OS. hlahan, D. & G.
   lachen, OHG. hlahhan, lahhan, lahh?n, Icel. hl[ae]ja. Dan.
   lee, Sw. le, Goth. hlahjan; perh. of imitative origin.]
   1. To show mirth, satisfaction, or derision, by peculiar
      movement of the muscles of the face, particularly of the
      mouth, causing a lighting up of the face and eyes, and
      usually accompanied by the emission of explosive or
      chuckling sounds from the chest and throat; to indulge in
      laughter.

            Queen Hecuba laughed that her eyes ran o'er. --Shak.

            He laugheth that winneth.             --Heywood's
                                                  Prov.

   2. Fig.: To be or appear gay, cheerful, pleasant, mirthful,
      lively, or brilliant; to sparkle; to sport.

            Then laughs the childish year, with flowerets
            crowned.                              --Dryden.

            In Folly's cup still laughs the bubble Joy. --Pope.

   {To laugh at}, to make an object of laughter or ridicule; to
      make fun of; to deride.

            No wit to flatter left of all his store, No fool to
            laugh at, which he valued more.       --Pope.

   {To laugh in the sleeve}

Laugh \Laugh\, v. t.
   1. To affect or influence by means of laughter or ridicule.

            Will you laugh me asleep, for I am very heavy?
                                                  --Shak.

            I shall laugh myself to death.        --Shak.

   2. To express by, or utter with, laughter; -- with out.

            From his deep chest laughs out a loud applause.
                                                  --Shak.

   {To laugh away}.
      (a) To drive away by laughter; as, to laugh away regret.
      (b) To waste in hilarity. ``Pompey doth this day laugh
          away his fortune.'' --Shak.

   {To laugh down}.
      (a) To cause to cease or desist by laughter; as, to laugh
          down a speaker.
      (b) To cause to be given up on account of ridicule; as, to
          laugh down a reform.

   {To laugh one out of}, to cause one by laughter or ridicule
      to abandon or give up; as, to laugh one out of a plan or
      purpose.

   {To laugh to scorn}, to deride; to treat with mockery,
      contempt, and scorn; to despise.

Laugh \Laugh\, n.
   An expression of mirth peculiar to the human species; the
   sound heard in laughing; laughter. See {Laugh}, v. i.

         And the loud laugh that spoke the vacant mind.
                                                  --Goldsmith.

         That man is a bad man who has not within him the power
         of a hearty laugh.                       --F. W.
                                                  Robertson.

Source : WordNet®

laugh
     n 1: the sound of laughing [syn: {laughter}]
     2: a facial expression characteristic of a person laughing;
        "his face wrinkled in a silent laugh of derision"
     3: a humorous anecdote or remark intended to provoke laughter;
        "he told a very funny joke"; "he knows a million gags";
        "thanks for the laugh"; "he laughed unpleasantly at hisown
        jest"; "even a schoolboy's jape is supposed to have some
        ascertainable point" [syn: {joke}, {gag}, {jest}, {jape}]

laugh
     v : produce laughter [syn: {express joy}, {express mirth}] [ant:
          {cry}]