Torus

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torus

[′tȯr·əs]
(anatomy)
A rounded protuberance occurring on a body part.
(botany)
The thickened membrane closing a bordered pit.
(mathematics)
The surface of a doughnut-shaped object.
The topological space obtained by identifying the opposite sides of a rectangle.
The group which is the product of two circles.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Torus

 

a geometric solid formed by the rotation of a circle about a line lying in the plane of the circle but not intersecting the circle (see Figure 1). A torus is shaped approximately like a doughnut or a life ring. If the radius of the rotating circle is r and

Figure 1

the distance from the center of the circle to the axis of rotation is a, then the area of the surface of the torus is 4π2ar and the volume of the torus is 2π2ar2. The term “torus” is also applied to the surface bounding such a solid.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

torus

torus molding
torus
A bold projecting molding, convex in shape, generally forming the lowest member of a base over the plinth.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.