phosgene, a. [Gr. fw^s light + the root of gi`gnesqai to be born: cf. F. phosgène.].
Producing, or produced by, the action of light; -- used specifically to designate a gas also called carbonyl chloride. See Carbonyl. [1913 Webster]
phosgene, n.
A reactive chemical substance (COCl2), also called carbonyl choride, used in synthesis of numerous substances. In the First Worlds War it was also used as a poisonous gas in combat. [PJC]