Source : Webster's Revised Unabridged Dictionary (1913)

Rehearsal \Re*hears"al\ (r?*h?rs"a), n.
   The act of rehearsing; recital; narration; repetition;
   specifically, a private recital, performance, or season of
   practice, in preparation for a public exhibition or exercise.
   --Chaucer.

         In rehearsal of our Lord's Prayer.       --Hooker.

         Here's marvelous convenient place for our rehearsal.
                                                  --Shak.

   {Dress rehearsal} (Theater), a private preparatory
      performance of a drama, opera, etc., in costume.

Source : WordNet®

dress rehearsal
     n : a full uninterrupted rehearsal in costumes shortly before
         the first performance