Source : Webster's Revised Unabridged Dictionary (1913)

Phosgene \Phos"gene\, a. [Gr. ? light + the root of ? to be
   born: cf. F. phosg[`e]ne.] (Old Chem.)
   Producing, or produced by, the action of light; -- formerly
   used specifically to designate a gas now called {carbonyl
   chloride}. See {Carbonyl}.

Source : WordNet®

phosgene
     n : a colorless poisonous gas that smells like new-mown hay;
         used in chemical warfare