cosine
UK /ˈkəʊ.saɪn/ · US /ˈkoʊ.saɪn/ noun
Forms cosines
- noun (trigonometry) In a right triangle, the ratio of the length of the side adjacent to an acute angle to the length of the hypotenuse. Symbol: cos
Synonyms
Etymology
From co- + sine, short for complementi sinus in Latin, meaning “sine of the complement”. Doublet of cosinus.
Webster’s 1913
- noun The sine of the complement of an arc or angle. See Illust. of Functions.
Etymology [For co. sinus, an abbrev. of L. complementi sinus.]
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “cosine”, CC BY-SA 4.0. Details