Source : Webster's Revised Unabridged Dictionary (1913)

Negro \Ne"gro\, n.; pl. {Negroes}. [Sp. or Pg. negro, fr. negro
   black, L. niger; perh. akin to E. night.]
   A black man; especially, one of a race of black or very dark
   persons who inhabit the greater part of tropical Africa, and
   are distinguished by crisped or curly hair, flat noses, and
   thick protruding lips; also, any black person of unmixed
   African blood, wherever found.

Source : WordNet®

negroes
     See {negro}

negro
     adj : relating to or characteristic of or being a member of the
           traditional racial division of mankind having brown to
           black pigmentation and tightly curled hair
     [also: {negroes} (pl)]