Definition of black walnut in English:

black walnut

noun

  • Any of a group of North and South American walnut trees producing four-chambered nuts with indehiscent hulls, especially Juglans nigra, chiefly of eastern and central areas; (also) the heavy dark-coloured timber of any of these trees; frequently with distinguishing word.

Origin

Early 17th century; earliest use found in John Pory (bap. 1572, d. ?1636), writer and colonial administrator.