D defs.my
Entry 1 sense Webster, 1913

Ravelin

/(răv"lĭn; 277)/ · Rave·lin · IPA
01 n. A detached work with two embankments which make a salient angle. It is raised before the curtain on the counterscarp of the place. Formerly…
  1. 1.
    A detached work with two embankments which make a salient angle. It is raised before the curtain on the counterscarp of the place. Formerly called demilune and half-moon.(Fort.) Also: demilune, half-moon