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.
An edge around something, especially when circular.
A wheelrim.
A membrane.
A semicircular copydesk.
To form a rim on.
To roll around a rim.
To lick the anus of a partner as a sexual act.
To follow the contours, possibly creating a circuit.