redoubt (n.)
- abatis
- bank
- banquette
- barbican
- barricade
- barrier
- bastion
- battlement
- breastwork
- bulwark
- cheval-de-frise
- citadel
- curtain
- dike
- drawbridge
- earthwork
- enclosure
- entanglement
- escarp
- escarpment
- fastness
- fence
- fieldwork
- fortification
- fortress
- loophole
- lunette
- machicolation
- mantelet
- merlon
- mound
- outwork
- palisade
- parapet
- portcullis
- rampart
- scarp
- sconce
- stockade
- stronghold
- work