[ ee-kwuh-lat-er-uhl, ek-wuh- ]
See synonyms for equilateral on Thesaurus.com
  1. having all the sides equal: an equilateral triangle.

  1. a figure having all its sides equal.

  2. a side equivalent, or equal, to others.

Origin of equilateral

From the Late Latin word aequilaterālis, dating back to 1560–70. See equi-, lateral

Other words from equilateral

  • e·qui·lat·er·al·ly, adverb
  • non·e·qui·lat·er·al, adjective
  • non·e·qui·lat·er·al·ly, adverb
  • sub·e·qui·lat·er·al, adjective
  • un·e·qui·lat·er·al, adjective
  • un·e·qui·lat·er·al·ly, adverb

Words Nearby equilateral

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How to use equilateral in a sentence

British Dictionary definitions for equilateral


/ (ˌiːkwɪˈlætərəl) /

  1. having all sides of equal length: an equilateral triangle

  1. a geometric figure having all its sides of equal length

  2. a side that is equal in length to other sides

Derived forms of equilateral

  • equilaterally, adverb

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

Scientific definitions for equilateral


[ ē′kwə-lătər-əl ]

  1. Having all sides of equal length, as a triangle that is neither scalene nor isosceles.

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