Phosgene

Phosgene , adjective

[Greek fw^s light + the root of gi`gnesqai to be born: compare French phosgène.]

(Old Chemistry) Producing, or produced by, the action of light; -- used specifically to designate a gas also called carbonyl chloride. See phosgene, n., and Carbonyl.

phosgene (fos"jēn or foz"jēn) , noun

(Chemistry) A reactive chemical substance (COCl2), also called carbonyl choride, used in synthesis of numerous substances. In the First World War it was also used as a poisonous gas in combat.