Source : Webster's Revised Unabridged Dictionary (1913)

Abbess \Ab"bess\ ([a^]b"b[e^]s), n. [OF. abaesse, abeesse, F.
   abbesse, L. abbatissa, fem. of abbas, abbatis, abbot. See
   {Abbot}.]
   A female superior or governess of a nunnery, or convent of
   nuns, having the same authority over the nuns which the
   abbots have over the monks. See {Abbey}.

Source : WordNet®

abbess
     n : the superior of a group of nuns [syn: {mother superior}, {prioress}]