'City of David' in the Bible

Nevertheless, David captured the stronghold (fortress) of Zion, that is, the City of David.

So David lived in the stronghold and called it the City of David. And he built all around [the surrounding area] from the Millo [fortification] and inward.

David was unwilling to move the ark of the Lord into the City of David with him; instead he took it aside to the house of Obed-edom the Gittite.

Now King David was told, “The Lord has blessed the house of Obed-edom and all that belongs to him, because of the ark of God.” So David went and brought up the ark of God from the house of Obed-edom into the City of David with rejoicing and gladness.

Then, as the ark of the Lord came into the City of David, Michal, Saul’s daughter [David’s wife], looked down from the window above and saw King David leaping and dancing before the Lord; and she felt contempt for him in her heart [because she thought him undignified].