1911 Encyclopædia Britannica/Enfilade

ENFILADE (a French word, from enfiler, to thread, and so to pass through from end to end), a military term used to express the direction of fire along an enemy’s line, or parapet. This species of fire is most demoralizing and destructive, since, from its direction, very few guns or rifles can be brought to bear to meet it. If any considerable body of men changes front, it immediately lays itself open to enfilade from the enemy whom it originally faced. Against entrenchments, or the parapets of fortifications, enfilade is still more effective, as the enemy is deprived of the protection given by his works and is no better covered than if he were in the open. Banks of earth, built perpendicular to the line of defence (called traverses), are usually employed to protect parapets or trenches against enfilade.