torus

[tawr-uhs]

noun

plural

tori 

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.

2. Geometry.

   1. Rarely a doughnut-shaped surface generated by the revolution of a conic section, especially a circle, about an exterior line lying in its plane.

   2. the solid enclosed by such a surface.

3. Botany.

   1. the receptacle of a flower.

   2. 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.

torus

/ ˈtɔːrəs /

noun

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: 4π² Rr ; volume: 2π² Rr ², 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

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

plural

tori 

1. 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.

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

Word History and Origins

Origin of torus¹

First recorded in 1555–65; from Latin: literally, “strand, thong, raised ridge”

Word History and Origins

Origin of torus¹

C16: from Latin: a swelling, of obscure origin