diameter

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diameter

a. a straight line connecting the centre of a geometric figure, esp a circle or sphere, with two points on the perimeter or surface
b. the length of such a line
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Diameter

 

The diameter of a circle is the chord that passes through the center of the circle. Moreover, the diameter of a circle is the length of this chord, equal to two radii.

In analytic geometry the diameter of a conic section (or of a curve of the second order) is understood to mean the straight line that passes through the midpoints of a set of parallel chords. For central curves of the second order (circles, ellipses, hyperbolas) this is the straight line passing through the center of the curve. In the case of the parabola, all diameters are parallel to its axis.

The concept of the diameter of a circle as the length of a segment is applied to other geometric figures and to sets of a more general nature. The diameter of a figure (or a set in metric space) is precisely the upper bound of the distances between all possible pairs of points of this figure. In this sense, the diameter of an ellipse is equal to the length of the semimajor axis, and the diameter of a square is equal to the length of its diagonal.

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

diameter

[dī′am·əd·ər]
(mathematics)
A line segment which passes through the center of a circle, and whose end points lie on the circle.
The length of such a line.
For a conic, any straight line that passes through the midpoints of all the chords of the conic that are parallel to a given chord.
For a set, the smallest number that is greater than or equal to the distance between every pair of points of the set.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

diameter

The diameter of a graph is the maximum value of the minimum distance between any two nodes.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

Diameter

An authentication, authorization and accounting (AAA) protocol that replaces RADIUS (Diameter is a play on the word RADIUS). Like RADIUS, Diameter uses a challenge/response method; however, unlike RADIUS, Diameter uses the reliable TCP and SCTP protocols rather than the unreliable UDP for transport. Diameter also supports error reporting and is better at scaling than RADIUS. See RADIUS, network access server and challenge/response.
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.
References in periodicals archive ?
The land-to-land diameter is roughly the same as the boring tool, so the land-to-land dimension is also called the bore diameter.
In our study, we measured the widest point of these two vessels using magnetic resonance imaging (MRI), in cases diagnosed with breast cancer or fibroadenoma by biopsy and compared with the vessel diameters of contralateral breast without lesions.
In this study, on the basis of literature [15, 16], transverse diameters (dorsal transverse, intermediary transverse, ventral transverse, cranial transverse, caudal transverse, and medial transverse diameters), oblique diameters (right oblique diameter, left oblique diameter, right sacrocotyloid diameter, and left sacrocotyloid diameter), conjugate diameters (conjugata vera and conjugata diagonalis), vertical diameter, pelvic inclination, and angle between arcus ischiadicus were measured (as shown in Figures 2-5).
* The association of crural arteries with respect to their different mean diameters was studied and 13 different patterns were found in the present study as compared to 24 different (variant) patterns reported by Szpinda.
The user specifies additional ranges of cells containing diameters of the stocks and parts, and 1DCutX uses only such stocks that have the same diameter as required parts.
Sylvie Nguyen The Tich of University Hospital, Angers, France, and her colleagues, also found that this biparietal diameter is significantly larger in term newborns than in preterm newborns when measured at term equivalent age.
To ensure that a given tool can successfully inspect all sections of a pipeline with changing diameter sizes, the correct tool type and size must be used.
* Shaft supports with a built-in damper, which can accommodate 12- to 30-mm shaft diameters, to reduce shaft damage.
The median diameters at which particles exhibit aerosol behavior also correspond to the sizes at which they are efficiently deposited in the lower respiratory tract when inhaled.
Rolyn now offers precision molded polymer aspheric lenses for infinity conjugates in both 12.7 and 25.4 mm diameters. All 12.7 mm diameter lenses have an 11.4 mm clear aperture.
A relatively simple and inexpensive mechanical system changes pipe and calibrator diameters in 15 minutes, as compared with an hour or two for standard pipe systems.