Source : Webster's Revised Unabridged Dictionary (1913)

Cosine \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}.

Source : WordNet®

cosine
     n : ratio of the adjacent side to the hypotenuse of a
         right-angled triangle [syn: {cos}]

Source : Free On-Line Dictionary of Computing

COSINE
     
        Cooperation for Open Systems Interconnection Networking in
        Europe.  A EUREKA project.