From Longman Dictionary of Contemporary Englishdoughnutdough‧nut /ˈdəʊnʌt $ ˈdoʊ-/ noun [countable] 
DFFa small round cake, often in the form of a ring
DFFa small round cake, often in the form of a ringExamples from the Corpus
doughnut• Why, Jo wondered, did she have to have a nose like a cross between a doughnut and a ski-jump?• A baker is asking his customers to choose between doughnuts made with blue, red, yellow and green icing.• Graceland is there, already, centerpiece of 10 dozen doughnut shops and roadside flophouses.• Their main source of income came from doughnuts.• He bought her doughnuts and cans of Carlsberg Special, and they picnicked on the pavement and he sang to her.• I took out another sugared doughnut and began devouring it.• The new structures have rejoiced in wonderfully evocative names like the beehive, the bell, the doughnut and the bicycle wheel.• A conveyor belt lifts the doughnuts out of the grease for a slow ride through a white curtain of falling glaze. 