torus

American  

[tawr-uhs] / ˈtɔr əs /

noun

tori plural

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.

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torus British  

/ 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

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torus Scientific  

/ tôr′əs /

tori plural

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.

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Other Word Forms

Noun Inflected Forms

• tori
  plural

Etymology

Origin of torus

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

Example Sentences

See Examples For:

torus tori

"The plasma torus gives us a way to know what's happening to the material near these stars, including where it's concentrated, how it's moving, and how strongly it is influenced by the star's magnetic field."

From Science Daily ● Mar. 27, 2026

A puffy donut-shaped cloud of material called a torus surrounds the accretion disk.

From Science Daily ● May 8, 2024

The torus wasn’t as bright as it should have been.

From New York Times ● Jan. 25, 2023

Or it could mean that the torus was rapidly diffusing in response to the intense eruption.

From New York Times ● Jan. 25, 2023

But the second, which aimed to open the valve on the torus, was pushed back by heat and radiation.

From "Meltdown" by Deirdre Langeland

First noted at a World Cup match 18 years ago in France, the practice is known as “Tatsu tori ato wo nigosazu” — a departing bird does not muddy the water.

From Los Angeles Times ● Jun. 22, 2026

By constructing a pair of tori that match in local measurements but differ globally, the team has provided the first explicit example of this phenomenon.

From Science Daily ● Apr. 22, 2026

No sound is needed to scare off seabirds with a device called a tori line.

From Washington Post ● Aug. 17, 2022

And now we replace each torus in the chain with another chain of smaller tori, in this case 18 again.

From Scientific American ● Jul. 8, 2018

The octagonal stone spire has angles rounded by tori, with a small gable with thin columns in the extension of each opening.

From Romanesque Art in Southern Manche: Album by Lebert, Marie