Torus

noun, plural tori
[tawr-ahy, tohr-ahy] /ˈtɔr aɪ, ˈtoʊr aɪ/ (Show IPA)
1.
Architecture. a large convex molding, more or less semicircular in profile, commonly forming the lowest molding of the base of a column, directly above the plinth, sometimes occurring as one of a pair separated by a scotia and fillets. and column.
2.
Geometry.

a doughnut-shaped surface generated by the revolution of a conic, especially a circle, about an exterior line lying in its plane.
the solid enclosed by such a surface.

3.
Botany.

the receptacle of a flower.
a thickening of the wall membrane in the bordered pits occurring in the tracheid cells of the wood of many conifers.

4.
Anatomy. a rounded ridge; a protuberant part.
noun (pl) -ri (-raɪ)
1.
Also called tore. a large convex moulding approximately semicircular in cross section, esp one used on the base of a classical column
2.
(geometry) a ring-shaped surface generated by rotating a circle about a coplanar line that does not intersect the circle. Area: 4π²Rr; volume: 2π²Rr², where r is the radius of the circle and R is the distance from the line to the centre of the circle
3.
(botany) another name for receptacle (sense 2)
4.
(anatomy) a ridge, fold, or similar linear elevation
5.
(astronomy) a dense ring of gas and dust which surrounds a dying star, containing most of the star’s ejected gas

torus to·rus (tôr’əs)
n. pl. to·ri (tôr’ī)
A bulging or rounded projection or swelling, such as is caused by a bone or muscle.
torus
(tôr’əs)
Plural tori (tôr’ī)

A surface generated by rotating a circle about an axis that is in the same plane as the circle but does not intersect it. A torus resembles a donut and is a subtype of toroid.

The torus-shaped apparatus that contains plasma in nuclear fusion reactors.