How to say "citadel" in Japanese

• 城郭じょうかくCommon
  nounCovers citadel in its concrete sense: a fortified castle or fortress, thought of as a structure with walls and defenses. This is the word for an actual military fortification.
• 根城ねじろCommon
  nounCovers the stronghold sense of citadel: a fortified base from which one operates or holds out. It also has figurative uses, for a place that serves as someone's base of activity.

Use 城郭 for citadel as a concrete fortified castle or fortress structure, and 根城 for the stronghold sense, including figurative uses where a place serves as someone's base.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 城郭じょうかくcastle
• 根城ねじろstronghold
• 城塞じょうさいfortress