Other forms: donuts
A donut is the sweet fried ring with a hole in the middle. A jam donut, a box of donuts, glazed donuts.
The hole exists for cooking rather than looks — it lets the middle cook through before the outside burns. This spelling is the American short form; doughnut is the older and British one. A donut in engineering means anything ring-shaped.
1noundonutA sweet fried ring of dough.
“He grabbed a coffee and a donut on his way to work.”
donut is a cake.
Also accepted in games: doughnut
An altered spelling of doughnut, from dough plus nut, attested from 1900. The nut named a small fried lump of dough.
From doughnut. Alteration of doughnut, from dough + nut. Attested 1900.
Etymology from Wiktionary, CC BY-SA