A deep-fried piece of dough or batter, commonly of a toroidal (a ring doughnut) shape, often mixed with various sweeteners and flavourings; or flattened sphere (a filled doughnut) shape filled with jam, custard or cream.
Anything in the shape of a torus.
A peel-out or skid mark in the shape of a circle; a 360-degree skid.
A spare car tyre, usually stored in the boot, that is smaller than a full-sized tyre and is only intended for temporary use.
A vulva.
(colloquial) A foolish or stupid person.