Meuse
Texas tower
abatis
advanced work
air hole
alternative
aperture
armhole
avenue
balistraria
bank
banquette
barbed-wire entanglement
barbican
barricade
barrier
bartizan
bastion
battlement
beacon
belvedere
bleachers
blowhole
breastwork
bridge
bullet-hole
bulwark
bunghole
casemate
channel
cheval-de-frise
choice
chute
circumvallation
conning tower
contravallation
counterscarp
cringle
curtain
deadeye
debouch
demibastion
dike
dodge
door
drawbridge
earthwork
egress
embrasure
emunctory
ambiguity
hole
loopholed
loopholes
battlements
crevice
flaw
opening
escape clause