What is "retirade"

Retirade \Ret`i*rade"\, n. [F.; cf. Sp. retirada retreat. See Retire.] (Fort.) A kind of retrenchment, as in the body of a bastion, which may be disputed inch by inch after the defenses are dismantled. It usually consists of two faces which make a re["e]ntering angle.

n. A kind of retrenchment, as in the body of a bastion, which may be disputed inch by inch after the defenses are dismantled. It usually consists of two faces which make a reentering angle.