Definition of cosecant
1 : a trigonometric function that for an acute angle is the ratio between the hypotenuse of a right triangle of which the angle is considered part and the leg opposite the angle
2 : a trigonometric function csc θ that is the reciprocal of the sine for all real numbers θ for which the sine is not zero and that is exactly equal to the cosecant of an angle of measure θ in radians
Origin of cosecant
New Latin cosecant-, cosecans, from co- + secant-, secans secant
First Known Use: circa 1706
Learn More about cosecant
Britannica.com: Encyclopedia article about "cosecant"
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