unit circle

noun

: a circle having a radius of 1

Examples of unit circle in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
To see how to create a 17-gon, start with a unit circle (where the radius equals one) and a point A on the circle. Jack Murtagh, Scientific American, 12 Sep. 2024 This is the region under the unit circle, defined by y=, that lies above the portion of the horizontal axis from 0 to x. Steven Strogatz, Quanta Magazine, 31 Aug. 2022 Since going a distance π takes you halfway around the unit circle, cos(π)=-1 and sin(π)=0, so eiπ=-1. Lorenzo Sadun, Slate Magazine, 14 Mar. 2017

Word History

First Known Use

1852, in the meaning defined above

Time Traveler
The first known use of unit circle was in 1852

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Cite this Entry

“Unit circle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unit%20circle. Accessed 9 Sep. 2025.

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