noun \ˈsīn\

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

Full Definition of SINE

:  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
:  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 of SINE

Medieval Latin sinus, from Latin, curve
First Known Use: 1593
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