Source : Webster's Revised Unabridged Dictionary (1913)

Fumigation \Fum`iga"tion\, n. [Cf. F. fumigation.]
   1. The act of fumigating, or applying smoke or vapor, as for
      disinfection.

   2. Vapor raised in the process of fumigating.

Source : WordNet®

fumigation
     n : the application of a gas or smoke to something for the
         purpose of disinfecting it