The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster] Cosmetic

WordNet (r) 3.0 (2006):

cosine
    n 1: ratio of the adjacent side to the hypotenuse of a right-
         angled triangle [syn: cosine, cos]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

COSINE
       Cooperation for OSI Networking in Europe (org.)


The Free On-line Dictionary of Computing (30 December 2018):

COSINE

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