caisson

nouns

an ornamental sunken panel in a ceiling or dome
caisson, coffer, lacuna
a two-wheeled military vehicle carrying artillery ammunition
caisson
domain category
the military forces of a nation
"their military is the largest in the region"; "the military machine is the same one we faced in 1991 but now it is weaker"
armed forces, armed services, military, military machine, war machine
is a type of (narrower)
vehicle used by the armed forces
military vehicle
a chest to hold ammunition
ammunition chest, caisson
large watertight chamber used for construction under water
caisson, cofferdam, pneumatic caisson