# diameter

[ dahy-am-i-ter ]

/ daɪˈæm ɪ tər /

### noun

Geometry.

- a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end.
- a straight line passing from side to side of any figure or body, through its center.

the length of such a line.

the width of a circular or cylindrical object.

## RELATED CONTENT

## Nearby words

## Origin of diameter

Can be confusedcircumference diameter radius tangent

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

## Examples from the Web for diameter

## British Dictionary definitions for diameter

## diameter

/ (daɪˈæmɪtə) /

### noun

- a straight line connecting the centre of a geometric figure, esp a circle or sphere, with two points on the perimeter or surface
- the length of such a line

the thickness of something, esp with circular cross section

## Word Origin for diameter

C14: from Medieval Latin diametrus, variant of Latin diametros, from Greek: diameter, diagonal, from dia- + metron measure

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

## Word Origin and History for diameter

## diameter

late 14c., from Old French diametre, from Latin diametrus, from Greek diametros (gramme) "diagonal of a circle," from dia- "across, through" (see dia-) + metron "a measure" (see meter (n.2)).

Online Etymology Dictionary, © 2010 Douglas Harper

## Medicine definitions for diameter

## diameter

[ dī-ăm′ĭ-tər ]

### n.

A straight line connecting two opposite points on the surface of a spherical or cylindrical body, or at the boundary of an opening or foramen, passing through the center of such body or opening.

The distance measured along such a line.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

## Science definitions for diameter

## diameter

[ dī-ăm′ĭ-tər ]

A straight line segment that passes through the center of a circle or sphere from one side to the other.

The length of such a line segment.

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

## Culture definitions for diameter

## diameter

[ (deye-am-uh-tuhr) ]

A straight line passing through the center of a figure, especially a circle or sphere, and joining two opposite points on its circumference.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.