'Fortress' in the Bible

The inhabitants of Jebus told David, "You're not coming in here!" Nevertheless, David captured the fortress of Zion, now known as the City of David.

David occupied the fortress, so it was named the City of David after him.

and David is then in the fortress, and the station of the Philistines is then in Beth-Lehem,

And of the Gadite there have been separated unto David, to the fortress, to the wilderness, mighty of valour, men of the host for battle, setting in array target and buckler, and their faces the face of the lion, and as roes on the mountains for speed:

And some of the sons of Benjamin and [from] Judah came to the fortress, to David.