ra·​di·​an | \ ˈrā-dē-ən How to pronounce radian (audio) \

Definition of radian

: a unit of plane angular measurement that is equal to the angle at the center of a circle subtended by an arc whose length equals the radius or approximately 57.3 degrees

Examples of radian in a Sentence

Recent Examples on the Web This puts the angular velocity at 93.65 radians per second. Adam Rogers, WIRED, 10 July 2019 These units are called radians (apologies if this term provokes a violent and sickening flashback to high school math), and there are 2π of them in a circle. Brian Resnick, Vox, 13 Mar. 2019 Three quarters around the same circle has gone one and a half pi radians. Randyn Charles Bartholomew, Scientific American, 25 June 2014 According to People, the elongated radian cut ring is 4 carats, and was personally designed by Zandy along with Leor Yerushalmi and The Jewelers of Las Vegas. De Elizabeth, Teen Vogue, 29 Apr. 2018 For example, pi can be measured according to radians, the standard unit for angular measurements. Jay Bennett, Popular Mechanics, 14 Mar. 2018 Radian was required to set aside reserves against potential losses on bad loans, and Mr. Lutz reckoned that his employer was materially understating those amounts. Gretchen Morgenson, New York Times, 28 Apr. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radian.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of radian

1879, in the meaning defined above

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Dictionary Entries Near radian

radial velocity



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Cite this Entry

“Radian.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radian. Accessed 24 Jan. 2022.

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More Definitions for radian


ra·​di·​an | \ ˈrād-ē-ən How to pronounce radian (audio) \

Medical Definition of radian

: a unit of plane angular measurement that is equal to the angle at the center of a circle subtended by an arc equal in length to the radius

More from Merriam-Webster on radian

Nglish: Translation of radian for Spanish Speakers

Britannica.com: Encyclopedia article about radian


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