Bifrost
abatis
advanced work
balistraria
bank
banquette
barbed-wire entanglement
barbican
barricade
barrier
bartizan
bascule bridge
bastion
bateau bridge
battlement
breastwork
bridge
bulwark
cantilever bridge
casemate
catwalk
cheval-de-frise
circumvallation
contravallation
counterscarp
curtain
demibastion
dike
earthwork
enclosure
entanglement
escarp
escarpment
fence
fieldwork
floating bridge
flyover
footbridge
fortalice
fortification
gangboard
gangplank
gangway
glacis
lift bridge
loophole
lunette
machicolation
mantelet
merlon
span
archway
bailey
battlements
causeway
citadel
dyke
jetty
moat
palisade
portcullis
pylon
rampart
stockade
turret
viaduct