The Collaborative International Dictionary of English v.0.48:
Dyke \Dyke\, n. See Dike. The spelling dyke is restricted by some to the geological meaning. [1913 Webster]WordNet (r) 3.0 (2006):
dyke n 1: (slang) offensive term for a lesbian who is noticeably masculine [syn: butch, dike, dyke] 2: a barrier constructed to contain the flow of water or to keep out the sea [syn: dam, dike, dyke] v 1: enclose with a dike; "dike the land to protect it from water" [syn: dike, dyke]