Webster's Revised Unabridged Dictionary · 1913

Bastion

Bastion (bas"chun; 106) , noun

[French bastion (compare Italian bastione), from Late Latin bastire to build (compare French bâtir, Italian bastire), perh. from the idea of support for a weight, and akin to Greek basta`zein to lift, carry, and to English baston, baton.]

(Fortification) A work projecting outward from the main inclosure of a fortification, consisting of two faces and two flanks, and so constructed that it is able to defend by a flanking fire the adjacent curtain, or wall which extends from one bastion to another. Two adjacent bastions are connected by the curtain, which joins the flank of one with the adjacent flank of the other. The distance between the flanks of a bastion is called the gorge. A lunette is a detached bastion. See Ravelin.