defence force, defense force, defence, defense - an organization of defenders that provides resistance against attack; "he joined the defense against invasion"

acropolis - the citadel in ancient Greek towns

kremlin - citadel of a Russian town

Kremlin - citadel of Moscow, housing the offices of the Russian government

stronghold, fastness - a strongly fortified defensive structure

fortification, munition - defensive structure consisting of walls or mounds built around a stronghold to strengthen it