Source : Webster's Revised Unabridged Dictionary (1913)

Deflagrate \Def"la*grate\, v. i. [imp. & p. p. {Deflagrated}; p.
   pr. & vb. n. {Deflagrating}.] [L. deflagratus, p. p. of
   deflagrare to burn up; de- + flagrare to flame, burn.]
   (Chem.)
   To burn with a sudden and sparkling combustion, as niter;
   also, to snap and crackle with slight explosions when heated,
   as salt.