Redan
in fortifications, work having two faces forming a salient angle in the direction from which an attack may be expected. It is open at the gorge.
A double redan has a re-entering angle for mutual defense. The redan is simplest field work, and is used for de fending the avenues of approach to a village, bridge, or defile. În front of another field work, it is called a fiéche.
When flanks are added to the faces, the work becomes a detached bastion or lunette.
RED CROSS