noun. That branch of fortification the object of which is to determine the directions or heights of the lines of rampart or parapet, so that the interior of the work may not be incommoded by a fire directed to it from neighboring eminences. Also defilement.

noun. The art or act of determining the directions and heights of the lines of rampart with reference to the protection of the interior from exposure to an enemy's fire from any point within range, or from any works which may be erected.

verb. Present participle of defilade.

"The Colonel had arms taken at once and disposed the regiment north of the road which, being elevated, provided sufficient cover for defilading the men."

defilade