The Collaborative International Dictionary of English v.0.48:

Buckra \Buck"ra\, a.
   White; white man's; strong; good; as, buckra yam, a white
   yam.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Buckra \Buck"ra\, n. [In the language of the Calabar coast,
   buckra means "demon, a powerful and superior being." --J. L.
   Wilson.]
   A white man; -- a term used by negroes of the African coast,
   West Indies, etc.
   [1913 Webster]