The Collaborative International Dictionary of English v.0.48:

Breviary \Bre"vi*a*ry\, n.; pl. Breviaries. [F. br['e]viarie,
   L. breviarium summary, abridgment, neut. noun fr. breviarius
   abridged, fr. brevis short. See Brief, and cf. Brevier.]
   1. An abridgment; a compend; an epitome; a brief account or
      summary.
      [1913 Webster]

            A book entitled the abridgment or breviary of those
            roots that are to be cut up or gathered. --Holland.
      [1913 Webster]

   2. A book containing the daily public or canonical prayers of
      the Roman Catholic or of the Greek Church for the seven
      canonical hours, namely, matins and lauds, the first,
      third, sixth, and ninth hours, vespers, and compline; --
      distinguished from the missal.
      [1913 Webster]

WordNet (r) 3.0 (2006):

breviary
    n 1: (Roman Catholic Church) a book of prayers to be recited
         daily certain priests and members of religious orders