D defs.my
Entry 1 sense Webster, 1913

Citadel

/sĭt'-əd-ĕlˌ/ · Cit·a·del · IPA /ˈsɪtədəl/
01 n. A fortress in or near a fortified city, commanding the city and fortifications, and intended as a final point of defense.
  1. 1.
    A fortress in or near a fortified city, commanding the city and fortifications, and intended as a final point of defense.
Syn. Stronghold. See Fortress.