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# sine

play
noun \ˈsīn\

## Simple 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

Source: Merriam-Webster's Learner's Dictionary

## Full Definition of sine

1. 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. 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

## Origin and Etymology of sine

Medieval Latin sinus, from Latin, curve

First Known Use: 1593

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