The Collaborative International Dictionary of English v.0.48:

Reveille \Re*veil"le\, n. [F. r['e]veil, fr. r['e]veiller to
   awake; pref. re- re- + pref. es- (L. ex) + veiller to awake,
   watch, L. vigilare to watch. The English form was prob. taken
   by mistake from the French imper. r['e]veillez,2d pers. pl.
   See Vigil.] (Mil.)
   The beat of drum, or bugle blast, about break of day, to give
   notice that it is time for the soldiers to rise, and for the
   sentinels to forbear challenging. "Sound a reveille."
   --Dryden.
   [1913 Webster]

         For at dawning to assail ye
         Here no bugles sound reveille.           --Sir W.
                                                  Scott.
   [1913 Webster]

WordNet (r) 3.0 (2006):

reveille
    n 1: (military) signal to wake up [syn: reveille, wake-up
         signal]
    2: a signal to get up in the morning; in the military it is a
       bugle call at sunrise

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "reveille":
   Angelus, Angelus bell, alarm, alarum, arousal, awakening,
   battle cry, birdcall, bugle call, call, last post, moose call,
   rallying cry, rebel yell, rousing, rude awakening, summons, taps,
   trumpet call, war cry, whistle



The Devil's Dictionary (1881-1906):

REVEILLE, n.  A signal to sleeping soldiers to dream of battlefields
no more, but get up and have their blue noses counted.  In the
American army it is ingeniously called "rev-e-lee," and to that
pronunciation our countrymen have pledged their lives, their
misfortunes and their sacred dishonor.