cos (Noun) — Ratio of the adjacent side to the hypotenuse of a right-angled triangle.
cos (Noun) — Lettuce with long dark-green leaves in a loosely packed elongated head.
cos (Noun) — A hard ferromagnetic silver-white bivalent or trivalent metallic element; a trace element in plant and animal nutrition.
cos (Conjunction) — For the reason that; on account of.