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# radian

[ rey-dee-uhn ]

/ ˈreɪ di ən /

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noun Mathematics.

the measure of a central angle subtending an arc equal in length to the radius: equal to 57.2958°. Abbreviation: rad

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## Words nearby radian

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

## How to use radian in a sentence

Strob, strob, n. the angular velocity of one radian per second.

The torsion couple per radian was determined by preliminary experiments.

## British Dictionary definitions for radian

radian

/ (ˈreɪdɪən) /

noun

an SI unit of plane angle; the angle between two radii of a circle that cut off on the circumference an arc equal in length to the radius. 1 radian is equivalent to 57.296 degrees and π/2 radians equals a right angleSymbol: rad

## Word Origin for radian

C19: from radius

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 radian

radian

[ rā′dē-ən ]

A supplementary unit of the International System used in angular measure. One radian is equal to the angle subtended at the center of a circle by an arc equal in length to the radius of the circle, approximately 57°17′44.6″.

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