Source : Webster's Revised Unabridged Dictionary (1913)

Defilade \De`fi*lade"\, v. t. [imp. & p. p. {Defiladed}; p. pr.
   & vb. n. {Defilading}.] [Cf. F. d['e]filer to defile, and
   d['e]filade act of defiling. See 1st {Defile}.] (Mil.)
   To raise, as a rampart, so as to shelter interior works
   commanded from some higher point.

Source : WordNet®

defilade
     n : the arrangement of defensive fortifications to protect
         against enemy fire