- the ratio of the hypotenuse to the opposite side of a given acute angle in a right triangle
- 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)

Origin of cosecant

French*cosécante,*for Modern Latin

*co. secans,*short for

*complementi secans,*literally , secant of the complement