Source : Webster's Revised Unabridged Dictionary (1913)

Evensong \E"ven*song`\, n. [AS. [=ae]fensang.]
   A song for the evening; the evening service or form of
   worship (in the Church of England including vespers and
   compline); also, the time of evensong. --Wyclif. Milton.

Source : WordNet®

evensong
     n 1: the sixth of the seven canonical hours of the divine office;
          early evening; now often made a public service on
          Sundays [syn: {vespers}]
     2: (Anglican Church) a daily evening service with prayers
        prescribed in the Book of Common Prayer [syn: {Evening
        Prayer}]