cosecant

noun

Trigonometry the reciprocal of the sine; specif.

1. the ratio of the hypotenuse to the opposite side of a given acute angle in a right triangle
2. an equivalent, positive or negative ratio for certain related angles (Ex.: the cosecant of 57° or 123° is 1.1923, of 237° or 303° is −1.1923) or real numbers representing radians (Ex.: the cosecant of .9948 radians (57°) is 1.1923)

Etymology: Fr cosécante, for co. secans, short for ModL complementi secans, lit., secant of the complement