torus (torus)

noun (plural tori /-rʌɪ/ or toruses)

• 1 Geometry a surface or solid formed by rotating a closed curve, especially a circle, about a line which lies in the same plane but does not intersect it (e.g. like a ring doughnut).
• a ring-shaped object, especially a large ring-shaped chamber used in physical research.

• 2 Architecture a large convex moulding, typically semicircular in cross section, especially as the lowest part of the base of a column.

• 3 Anatomy a ridge of bone or muscle: the maxillary torus

• 4 Botany the receptacle of a flower.