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 ]
n. (Chem.) An organic base, C6H6N4, produced artificially as a white, crystalline powder, by the action of ammonia on glyoxal. [ 1913 Webster ]