# Diagonal

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## diagonal

**1.**

*Maths*connecting any two vertices that in a polygon are not adjacent and in a polyhedron are not in the same face

**2.**

*Maths*a diagonal line or plane

**3.**

*Chess*any oblique row of squares of the same colour

**4.**cloth marked or woven with slanting lines or patterns

**5.**one front leg and the hind leg on the opposite side of a horse, which are on the ground together when the horse is trotting

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

## Diagonal

Joins two nonadjacent sides of a polygon with a slanted or oblique direction from one corner to the other; their use in a square or rectangle produces two triangular shapes.

Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

The following article is from

*The Great Soviet Encyclopedia*(1979). It might be outdated or ideologically biased.## Diagonal

a dense fabric of twisted cotton or wool yarn. Diagonals are characterized by sharp ribs on the surface running at an angle of more than 45° to the selvage. The ribs are obtained by proper selection of the ratio of the density and thickness of the warp and woof, as well as by the special interweaving of threads. Diagonal is used for uniforms (from wool warp and cotton woof), coats, and jackets.

## Diagonal

(1) The diagonal of a polygon is the line segment between two nonadjacent vertices. If the number of vertices of a polygon is *n*, then the number of diagonals is *n(n -3)12*.

(2) The diagonal of a polyhedron is the line segment between two vertices that do not lie on the same face.

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

## diagonal

[dī′ag·ən·əl] (civil engineering)

A sloping structural member, under compression or tension or both, of a truss or bracing system.

(mathematics)

The set of points all of whose coordinates are equal to one another in an

*n*-dimensional coordinate system.A line joining opposite vertices of a polygon with an even number of sides.

(optics)

A plane mirror or prism face mounted near the eyepiece of a telescope at an angle to the light path, to redirect the light for convenience of observation or to reduce the intensity of the image of the sun so that it can be observed directly.

(textiles)

A heavy twilled fabric.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

## diagonal

In a framed structure, an inclined member running across a panel, 7, e.g., as in a truss.

McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.