The Collaborative International Dictionary of English v.0.48:

Minstrel \Min"strel\, n. [OE. minstrel, menestral, OF.
   menestrel, fr. LL. ministerialis servant, workman (cf.
   ministrellus harpist), fr. L. ministerium service. See
   Ministry, and cf. Ministerial.]
   In the Middle Ages, one of an order of men who subsisted by
   the arts of poetry and music, and sang verses to the
   accompaniment of a harp or other instrument; in modern times,
   a poet; a bard; a singer and harper; a musician. --Chaucer.
   [1913 Webster]

WordNet (r) 3.0 (2006):

minstrel
    n 1: a singer of folk songs [syn: folk singer, jongleur,
         minstrel, poet-singer, troubadour]
    2: a performer in a minstrel show
    v 1: celebrate by singing, in the style of minstrels

The Devil's Dictionary (1881-1906):

MINSTREL, adj.  Formerly a poet, singer or musician; now a nigger with
a color less than skin deep and a humor more than flesh and blood can
bear.