9 Grammatical Pitfalls


[dahy-am-i-ter] /daɪˈæm ɪ tər/
  1. a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end.
  2. 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.
Origin of diameter
1350-1400; Middle English diametre < Old French < Latin diametros < Greek diámetros diagonal, diameter, equivalent to dia- dia- + -metros, derivative of métron meter1
Can be confused Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for diameter
  • The fountain consists of 32 jets in the middle of a 60-foot-diameter circle in which 159 granite boulders are arranged.
  • At an inch and a half in diameter, it is large as buttons go.
  • The diamond itself is about 2.5 centimeters in diameter.
  • To complete the scene, Pearson anchored the grove with a 48-inch-diameter stone-and-concrete globe.
  • On a lightly floured surface, roll dough into a circle at least 11 inches in diameter.
  • The asphalt connection is via wide, large-diameter tires with stubby sidewalls.
  • As far as I know the first number is the diameter and the second is the length.
  • In general, the larger the diameter of the pipe, the lower is the cost of transporting a given amount of oil.
  • Our inner 3.5″ diameter circle was a perfect fit for six snails.
  • It's the size of a hockey puck-small in diameter, plump in the middle-but juicy.
British Dictionary definitions for diameter


  1. a straight line connecting the centre of a geometric figure, esp a circle or sphere, with two points on the perimeter or surface
  2. the length of such a line
the thickness of something, esp with circular cross section
Word Origin
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
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Word Origin and History for 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
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diameter in Medicine

diameter di·am·e·ter (dī-ām'ĭ-tər)

  1. 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.

  2. 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.
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diameter in Science
  1. A straight line segment that passes through the center of a circle or sphere from one side to the other.

  2. The length of such a line segment.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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diameter in Culture
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 American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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diameter in Technology

The diameter of a graph is the maximum value of the minimum distance between any two nodes.

The Free On-line Dictionary of Computing, © Denis Howe 2010
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