sine

American  

[sahyn] / saɪn /

noun

1. Trigonometry.

   1. (in a right triangle) the ratio of the side opposite a given acute angle to the hypotenuse.

   2. (of an angle) a trigonometric function equal to the ratio of the ordinate of the end point of the arc to the radius vector of this end point, the origin being at the center of the circle on which the arc lies and the initial point of the arc being on the x-axis. sin

2. Geometry. (originally) a perpendicular line drawn from one extremity of an arc of a circle to the diameter that passes through its other extremity.

3. Mathematics. (of a real or complex numberx ) the function sin x defined by the infinite series x − (x 3 /3!) + (x 5 /5!) − + …, where ! denotes factorial.

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sine ¹ British  

/ ˈsaɪnɪ /

preposition

1. (esp in Latin phrases or legal terms) lacking; without

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sine ² British  

/ saɪn /

noun

1.  sin. 

   1. a trigonometric function that in a right-angled triangle is the ratio of the length of the opposite side to that of the hypotenuse

   2. a function that in a circle centred at the origin of a Cartesian coordinate system is the ratio of the ordinate of a point on the circumference to the radius of the circle

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sine Scientific  

/ sīn /

1. The ratio of the length of the side opposite an acute angle in a right triangle to the length of the hypotenuse.

2. The ordinate of the endpoint of an arc of a unit circle centered at the origin of a Cartesian coordinate system, the arc being of length x and measured counterclockwise from the point (1, 0) if x is positive or clockwise if x is negative.

3. A function of a number x, equal to the sine of an angle whose measure in radians is equal to x.

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Etymology

Origin of sine

1585–95; < New Latin, Latin sinus a curve, fold, pocket, translation of Arabic jayb literally, pocket, by folk etymology < Sanskrit jiyā, jyā chord of an arc, literally, bowstring

Example Sentences

Bone Sine in Portland, Ore., flecks its mix of nuts and chana dal with ground lime leaves.

From The Wall Street Journal • Dec. 17, 2025

Each spring semester, AU’s Sine Institute of Policy & Politics, which is focused on creating nonpartisan collaborations, hosts a cohort of marquee fellows for a semester-long seminar series.

From Washington Post • Feb. 9, 2023

Sine then, lots of economic factors — led by runaway inflation, supply chain disruptions and Russia’s invasion of Ukraine — have had a chilling effect on the economy.

From Seattle Times • Jan. 10, 2023

"We're hoping he comes back soon because he cuts all the logs," said Sine.

From BBC • Dec. 18, 2022

Sine enough, a piece of licorice jumps from his mouth, and guilt crawls into his eyes.

From "I Am the Messenger" by Markus Zusak