trapezoid

American  

[trap-uh-zoid] / ˈtræp əˌzɔɪd /

noun

trapezoids plural

1. Geometry.

   1. a quadrilateral plane figure having two parallel and two nonparallel sides.

   2. British. trapezium.

2. Anatomy. a bone in the wrist that articulates with the metacarpal bone of the forefinger.

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adjective

1. Geometry. Also trapezoidal. of, relating to, or having the form of a trapezoid.

trapezoid British  

/ ˈtræpɪˌzɔɪd /

noun

1. a quadrilateral having neither pair of sides parallel

2. Also called: trapezium.  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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trapezoid Scientific  

/ trăp′ĭ-zoid′ /

1. A four-sided plane figure having two parallel sides.

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trapezoid Cultural  

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

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Other Word Forms

Derived Forms

• posttrapezoid
  adjective
• subtrapezoid
  adjective
• subtrapezoidal
  adjective

Inflected Forms

Nouns

• trapezoids
  plural

Etymology

Origin of trapezoid

First recorded in 1695–1705; from New Latin trapezoīdēs, from Late Greek trapezoeidḗs “trapezium-like”; see trapezium, -oid

Explanation

In geometry a trapezoid is a four-sided figure with two sides that are parallel. Imagine taking an equilateral triangle and chopping its tip off so that it's made up of two parallel lines on top and bottom and you've got a trapezoid. The word trapezoid comes from the Greek trapeza meaning "table" and -oeides meaning "shaped." Think of a trapezoid as table-shaped. It has a pair of parallel sides that are also known as the bases of the figure. To find the area of a trapezoid, take the average of the bases and multiply it by the height. In anatomy, the trapezoid is the smallest of the eight small bones in the wrist.

Example Sentences

See Examples For:

trapezoid trapezoids

On a concrete plateau on a mountain overlooking the ice-dotted fjord sits the base’s radar building, a massive brutalist structure shaped like a concrete-and-steel trapezoid.

From The Wall Street Journal ● Oct. 12, 2025

I was hoping Joe would feel some similarly competitive outrage toward the rolling trapezoid, deficient in Americana, ignorant of history, nothing like the estimable Hummer.

From Slate ● Jun. 22, 2025

A trapezoid design in mid-century and Art Deco styles, it was met with surprise and pride: “Eric, this is a $50 clock,” his grandfather told him.

From Los Angeles Times ● Oct. 24, 2024

Each wire branch — ending in sheet-metal trapezoid and triangular petals painted primary blue, yellow, red and white — holds the next aloft, like dancers balancing on each other’s shoulders.

From Seattle Times ● Nov. 9, 2023

It was shaped like a wide trapezoid, and there were two indentations in the middle.

From "Tristan Strong Punches a Hole in the Sky" by Kwame Mbalia

Most dynamic are the pictures in which jauntily arranged trapezoids, grouped tightly together, appear to fracture.

From Washington Post ● Aug. 5, 2022

You can also hear the shape of parallelograms and acute trapezoids, according to a 2015 paper by Rowlett and Zhiqin Lu, a mathematician at the University of California, Irvine.

From Scientific American ● Jun. 28, 2022

The back half of the bike frame is a mess of intersecting triangles and trapezoids.

From The Verge ● Sep. 15, 2021

The trapezoidal rule for estimating definite integrals uses trapezoids rather than rectangles to approximate the area under a curve.

From Textbooks ● Mar. 30, 2016

Squares on the floor become trapezoids in a painting; everything gets gently distorted, but it looks perfectly natural to the viewer.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife