The Collaborative International Dictionary of English v.0.48:
Doughnut \Dough"nut\, n. A small cake (usually sweetened) fried in a kettle of boiling lard. [1913 Webster]WordNet (r) 3.0 (2006):
doughnut n 1: a toroidal shape; "a ring of ships in the harbor"; "a halo of smoke" [syn: ring, halo, annulus, doughnut, anchor ring] 2: a small ring-shaped friedcake [syn: doughnut, donut, sinker]