torus

to·rus (tôrs, tr-)
n. pl. to·ri (tôr, tr)
1. Architecture A large convex molding, semicircular in cross section, located at the base of a classical column.
2. Anatomy A bulging or rounded projection or swelling.
3. Botany The receptacle of a flower.
4. Mathematics A toroid generated by a circle; a surface having the shape of a doughnut. Also called tore2.