trench plough
Bassalia
abri
abysm
abyss
abyssal zone
adit
air-raid shelter
alley
approach
approach trench
aqueduct
arroyo
barge in
bathyal zone
benthos
bomb shelter
bombproof
bore
bottom
bottom glade
bottom waters
bottomless depths
bottoms
box canyon
boyau
breach
break
break in
break in upon
bunker
burrow
burst in
butt in
canal
canalization
canalize
canyon
carve
cave
cavity
chamfer
channel
channelize
chap
charge in
chasm
check
chimney
chink
chisel
cut
dig
dig out
excavate
fort
fortify
hollow
lay
place
pose
position
put
set
take advantage
trespass
trenched
trenches
trenching
tranche
battery
building
camp
crater
ditch
fortification
hole
lane
mound
pit
rampart
ravine
ridge
tank
tent
tunnel
valley
Bench
French
Hench
bench
clench
drench
entrench
french
hench
quench
rench
retrench
stench
tench
wrench
dike