Ravelin
Pronunciation : Rave"lin
Part of Speech : n.
Etymology : [F.; cf. Sp. rebellin, It. revellino, rivellino; perhaps fr. L. re- again + vallum wall.] (Fort.)
Definition : Defn: A detached work with two embankments with make a salient angle. It is raised before the curtain on the counterscarp of the place. Formerly called demilune and half-moon.
Source : Webster's Unabridged Dictionary, 1913