'Fortress' in the Bible

But David captured the fortress of Zion (that is, the city of David).

So David lived in the fortress and called it the City of David. David built all around it, from the terrace inwards.

When the Philistines heard that David had been designated king over Israel, they all went up to search for David. When David heard about it, he went down to the fortress.

Then they went to the fortress of Tyre and all the cities of the Hivites and the Canaanites. Then they went on to the Negev of Judah, to Beer Sheba.