Source : Webster's Revised Unabridged Dictionary (1913)

Deflagration \Def`la*gra"tion\, n. [L. deflagratio: cf. F.
   d['e]flagration.]
   1. A burning up; conflagration. ``Innumerable deluges and
      deflagrations.'' --Bp. Pearson.

   2. (Chem.) The act or process of deflagrating.

Source : WordNet®

deflagration
     n : combustion that propagates through a gas or along the
         surface of an explosive at a rapid rate driven by the
         transfer of heat