\ ˈsīn How to pronounce sine (audio) \

Definition of sine

1 : the trigonometric function that for an acute angle is the ratio between the leg opposite the angle when it is considered part of a right triangle and the hypotenuse
2 : a trigonometric function sin θ that for all real numbers θ is exactly equal to the sine of an angle of measure θ in radians and that is given by the sum of the alternating series {latex}\sin \theta = \theta - \frac{\theta^{3}}{3!} + \frac{\theta^{5}}{5!} - \frac{\theta^{7}}{7!} + \frac{\theta^{9}}{9!} - \dots{/latex}

Examples of sine in a Sentence

Recent Examples on the Web Aidan graduated from Saint John’s School this past weekend, sine laude. Kevin Fisher-paulson,, "Fisher-Paulson: As chapters of life begin and others end, it’s good to know your limitations," 16 June 2020 The bigger this angle, the bigger the sine, and therefore the stronger their mutual influence. Quanta Magazine, "Scientists Discover Exotic New Patterns of Synchronization," 4 Apr. 2019 When a pair of arrows are coupled, the strength of their mutual influence depends on the sine of the angle between their pointing directions. Quanta Magazine, "Scientists Discover Exotic New Patterns of Synchronization," 4 Apr. 2019 In four-wheel-drive, the Talon X is locked down and stable, even at 65 mph over sine-wave moguls that look like the earth’s furrowed brow. Ezra Dyer, Popular Mechanics, "Honda Talon X: The Ultimate Off-Road Toy," 4 Nov. 2019 His sine law allows anyone with a decent grounding in trigonometry to use a pendulum to determine their latitude. Alicia Ault, Smithsonian, "How Does Foucault’s Pendulum Prove the Earth Rotates?," 3 Feb. 2018 The link was so clear it could be described in derivative sines and cosines, mathematical concepts taught in college trigonometry. Brandon Keim, WIRED, "More Evidence Found for Quantum Physics in Photosynthesis," 6 Dec. 2011

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sine.' 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 sine

1593, in the meaning defined at sense 1

History and Etymology for sine

Medieval Latin sinus, from Latin, curve

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Statistics for sine

Last Updated

19 Jun 2020

Cite this Entry

“Sine.” Dictionary, Merriam-Webster, Accessed 8 Aug. 2020.

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How to pronounce sine (audio)

English Language Learners Definition of sine

geometry : the ratio between the long side (called the hypotenuse) and the side that is opposite to an acute angle in a right triangle

More from Merriam-Webster on sine

Britannica English: Translation of sine for Arabic Speakers Encyclopedia article about sine

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