Redan \Re*dan"\ (r?*d?n"), n. [F., for OF. redent a double
notching or jagging, as in the teeth of a saw, fr. L. pref.
re- re- + dens, dentis, a tooth. Cf. {Redented}.] [Written
sometimes {redent} and {redens}.]
1. (Fort.) A work having two parapets whose faces unite so as
to form a salient angle toward the enemy.
[1913 Webster]
2. A step or vertical offset in a wall on uneven ground, to
keep the parts level.
[1913 Webster]