Real Dictionary

doughnut
countable noun: A doughnut is a bread-like cake made from sweet dough that has been cooked in hot fat.

doughnut in American English
a small, usually ring-shaped cake of sweetened, leavened dough, fried in deep fat
noun: a small cake of sweetened or, sometimes, unsweetened dough fried in deep fat, typically shaped like a ring or, when prepared with a filling, a ball

doughnut in British English
noun: a small cake of sweetened dough, often ring-shaped or spherical with a jam or cream filling, cooked in hot fat
verb: (of Members of Parliament) to surround (a speaker) during the televising of Parliament to give the impression that the chamber is crowded or the speaker is well supported