2 Samuel 5:9

And David lived in the stronghold and called it the city of David . And David built the city all around from the Millo inward .

David then took up residence in the fortress and called it the City of David. He built up the area around it, from the terraces inward.

So David dwelt in the fort, and called it the city of David. And David built round about from Millo and inward.