'Fortress' in the Bible

And David captureth the fortress of Zion, it is the city of David.

And David dwelleth in the fortress, and calleth it -- City of David, and David buildeth round about, from Millo and inward,

And the Philistines hear that they have anointed David for king over Israel, and all the Philistines come up to seek David, and David heareth, and goeth down unto the fortress,

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

and they come in to the fortress of Tyre, and all the cities of the Hivite, and of the Canaanite, and go out unto the south of Judah, to Beer-Sheba.