1. [n]  a challenge to do something dangerous or foolhardy; "he could never refuse a dare"
2. [v]  challenge; "I dare you!"
3. [v]  take upon oneself; act presumptuously, without permission; "How dare you call my lawyer?"
4. [v]  to be courageous enough to try or do something; "I don't dare call him", "she dares to dress differently from the others."

1. \Dare\, v. i. [imp. {Durst}or {Dared}; p. p. {Dared}; p.
   pr. & vb. n. {Daring}.] [OE. I dar, dear, I dare, imp.
   dorste, durste, AS. ic dear I dare, imp. dorste. inf. durran;
   akin to OS. gidar, gidorsta, gidurran, OHG. tar, torsta,
   turran, Goth. gadar, gada['u]rsta, Gr. tharsei^n, tharrei^n,
   to be bold, tharsy`s bold, Skr. Dhrsh to be bold. [root]70.]
   To have adequate or sufficient courage for any purpose; to be
   bold or venturesome; not to be afraid; to venture.
         I dare do all that may become a man; Who dares do more
         is none.                                 --Shak.
         Why then did not the ministers use their new law?
         Bacause they durst not, because they could not.
                                                  --Macaulay.
         Who dared to sully her sweet love with suspicion.
                                                  --Thackeray.
         The tie of party was stronger than the tie of blood,
         because a partisan was more ready to dare without
         asking why.                              --Jowett
                                                  (Thu?yd.).
   Note: The present tense, I dare, is really an old past tense,
         so that the third person is he dare, but the form he
         dares is now often used, and will probably displace the
         obsolescent he dare, through grammatically as incorrect
         as he shalls or he cans. --Skeat.
               The pore dar plede (the poor man dare plead).
                                                  --P. Plowman.
               You know one dare not discover you. --Dryden.
               The fellow dares not deceive me.   --Shak.
               Here boldly spread thy hands, no venom'd weed
               Dares blister them, no slimy snail dare creep.
                                                  --Beau. & Fl.
   Note: Formerly durst was also used as the present. Sometimes
         the old form dare is found for durst or dared.
   

2. \Dare\, v. t. [imp. & p. p. {Dared}; p. pr. & vb. n.
   {Daring}.]
   1. To have courage for; to attempt courageously; to venture
      to do or to undertake.
            What high concentration of steady feeling makes men
            dare every thing and do anything?     --Bagehot.
            To wrest it from barbarism, to dare its solitudes.
                                                  --The Century.
   2. To challenge; to provoke; to defy.
            Time, I dare thee to discover Such a youth and such
            a lover.                              --Dryden.
   

3. \Dare\, n.
   1. The quality of daring; venturesomeness; boldness; dash.
      [R.]
            It lends a luster . . . A large dare to our great
            enterprise.                           --Shak.
   2. Defiance; challenge.
            Childish, unworthy dares Are not enought to part our
            powers.                               --Chapman.
            Sextus Pompeius Hath given the dare to C[ae]sar.
                                                  --Shak.
   

4. \Dare\, v. i. [OE. darien, to lie hidden, be timid.]
   To lurk; to lie hid. [Obs.] --Chaucer.
   

5. \Dare\, v. t.
   To terrify; to daunt. [Obs.]
         For I have done those follies, those mad mischiefs,
         Would dare a woman.                      --Beau. & Fl.
   {To dare larks}, to catch them by producing terror through to
      use of mirrors, scarlet cloth, a hawk, etc., so that they
      lie still till a net is thrown over them. --Nares.
   

6. \Dare\, n. [See {Dace}.] (Zo["o]l.)
   A small fish; the dace.
   

Differential Analyzer REplacement. A family of simulation languages for continuous systems.

["Digital Continuous System Simulation", G.A. Korn et al, P-H 1978].