'Strongholds' in the Bible

David stayed in the wilderness in strongholds, in the hill country of the Wilderness of Ziph. Saul searched for him every day, but God did not hand David over to him.

Then the Ziphites came to Saul at Gibeah, saying, “Is David not hiding with us in strongholds of Horesh, on the hill of Hachilah, which is south of Jeshimon?

David went up from there and stayed in the strongholds of Engedi.