A ring- or donut-shaped area or structure.
The ring of the sun not covered by the moon in an annular solar eclipse.
Structure in a fern that consists of differentially thick-walled cells on a sporangium that bend and distort as a result of drying.
The region in a plane between two concentric circles of different radii.
The membranous remnants of a partial veil which leaves a ring on the stem of a mushroom.
The space contained between the centre well bore and any external tubing. Sometimes used for separated gas flow.
Any topological space homeomorphic to the region in a plane between two concentric circles of different radius.
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.
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 kind of tyre for an airplane.
A vulva; (by extension) a woman's virginity.
A foolish or stupid person.
A circular life raft.
A toroidal vacuum chamber.