sine

noun

ˈsīn 

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

Where previously players could only activate one effect at a time, up to four effects can now sound simultaneously – with users able to choose from chorus, vibrato, flanger, delay (with tap tempo), reverb (acoustic, hall or plate) and tremolo (sine/triangle) out of the box. —Paul Ridden, New Atlas, 7 Oct. 2024

Six hundred years ago, mathematicians were building tables of sines and cosines, which were needed for navigation, but these can now be generated by computers in seconds. —Matteo Wong, The Atlantic, 4 Oct. 2024

Automorphic forms are a generalization of periodic functions like the sine in trigonometry, whose outputs endlessly repeat as inputs grow. —Kevin Hartnett, Quanta Magazine, 12 Oct. 2023

These functions, such as the sine and cosine, are defined using right triangles. —Leila Sloman, Scientific American, 10 Apr. 2023

Word History

Etymology

Medieval Latin sinus, from Latin, curve

First Known Use

1593, in the meaning defined at sense 1

Phrases Containing sine

• arc sine
• sine curve
• sine die
• sine qua non
• sine wave

Kids Definition

sine

noun

ˈsīn 

: a trigonometric function that for an acute angle in a right triangle is the ratio of the side opposite the angle to the hypotenuse