Emily Dickinson Lexicon

COP, n. [Sax. cop, or copp; W. cop, cob; D. kop; G. kopf; Fr. coupeau; Gr. κυβη.]

The head or top of a thing, as in cob-castle for cop-castle, a castle on a hill; a tuft on the head of birds. This word is little used in America, unless cob, the spike of maiz, may be the same word. – Chaucer.