[ tawr-uhs ]

noun,plural to·ri [tawr-ahy]. /ˈtɔr aɪ/.
  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.

    • Rarely an·chor ring . 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.

  1. 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.

  2. Anatomy. a rounded ridge; a protuberant part.

Origin of torus

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

Words Nearby torus Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use torus in a sentence

  • At this time each pistil loosens from the torus and can be easily removed, especially if some animal touch the hooks.

    Seed Dispersal | William J. Beal
  • The slender torus usually distinguished the eight-branch Plantagenet type, and its use here for simple diagonals is an exception.

    How France Built Her Cathedrals | Elizabeth Boyle O'Reilly
  • As time went on profiles deteriorated, sharp prismatic molds succeeding to the virile torus, or molds fluid and vague.

    How France Built Her Cathedrals | Elizabeth Boyle O'Reilly

British Dictionary definitions for torus


/ (ˈtɔːrəs) /

nounplural -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: 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

  1. botany another name for receptacle (def. 2)

  2. anatomy a ridge, fold, or similar linear elevation

  3. astronomy a dense ring of gas and dust which surrounds a dying star, containing most of the star's ejected gas

Origin of torus

C16: from Latin: a swelling, of obscure origin

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for torus


[ tôrəs ]

Plural tori (tôrī)
  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.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.