Vespers \Ves"pers\, n. pl. [OF. vespres, F. v[^e]pres, LL. vesperae, fr. L. vespera evening. See Vesper, n.]

(R. C. Ch.)
   (a) One of the little hours of the Breviary.
   (b) The evening song or service.

Sicilian vespers. See under Sicilian, a.

Source: Webster's Revised Unabridged Dictionary (1913)