Definitions for: Cosine

[n] ratio of the adjacent side to the hypotenuse of a right-angled triangle

Webster (1913) Definition: Co"sine (k?"s?n), n. [For co. sinus, an abbrev. of L.
complementi sinus.] (Trig.)
The sine of the complement of an arc or angle. See Illust. of
Functions.

Synonyms: cos

See Also: circular function, trigonometric function