access
adit
air lock
aisle
alley
ambulatory
aperture
approach
arcade
areaway
artery
avenue
breezeway
broaching
cavity
channel
chasm
check
clearing
cleft
cloister
colonnade
communication
conduit
connection
corridor
couloir
course
covered way
crack
defile
disclosure
ditch
duct
egress
entrance
entranceway
entry
entryway
exit
fenestra
ferry
fistula
fontanel
foramen
ford
gallery
gangplank
gangway
gap
passage
airlock
alcove
alleyway
archway
bulkhead
canyon
cavern
compartment
courtyard
foyer
grotto
hallway
hatchway
stairway
stairwell
thoroughfare
vault
vestibule
walkway