• synonyms


  1. Geometry.
    1. a quadrilateral plane figure having two parallel and two nonparallel sides.
    2. British.trapezium(def 1b).
  2. Anatomy. a bone in the wrist that articulates with the metacarpal bone of the forefinger.
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  1. Also trap·e·zoi·dal. Geometry. of, relating to, or having the form of a trapezoid.
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Origin of trapezoid

1695–1705; < New Latin trapezoīdēs < Late Greek trapezoeidḗs trapeziumlike. See trapezium, -oid
Related formspost·trap·e·zoid, adjectivesub·trap·e·zoid, adjectivesub·trap·e·zoi·dal, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for trapezoidal

Historical Examples

British Dictionary definitions for trapezoidal


  1. a quadrilateral having neither pair of sides parallel
  2. Also called: (Brit, Austral., NZ, and South African) trapezium US and Canadian a quadrilateral having two parallel sides of unequal length
  3. a small bone of the wrist near the base of the index finger
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Word Origin

C18: from New Latin trapezoidēs, from Late Greek trapezoeidēs trapezium-shaped, from trapeza table
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 trapezoidal



1706, "a trapezium," from Modern Latin trapezoides, from Late Greek trapezoeides (Proclus), special use by Euclid of Greek trapezoeides "trapezium-shaped," from trapeza, literally "table" (see trapezium), + -oeides "shaped" (see -oid). Technically, a quadrilateral figure with no two sides parallel. But in English since c.1800, often confused with trapezium in its sense of "a quadrilateral figure having only two sides parallel."

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Online Etymology Dictionary, © 2010 Douglas Harper

trapezoidal in Medicine


  1. A quadrilateral having two parallel sides.
  2. A small bone in the wrist that is situated near the base of the index finger and that articulates with the second metacarpal, trapezium, capitate, and scaphoid bones.
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Related formstrape•zoid′ null adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

trapezoidal in Science


  1. A four-sided plane figure having two parallel sides.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

trapezoidal in Culture



A four-sided polygon in which two sides are parallel and two are not.

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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.