'Outer' in the Bible

Hezekiah energetically rebuilt every broken wall. He erected towers and an outer wall, and fortified the terrace of the City of David. He made many weapons and shields.

After this Manasseh built up the outer wall of the City of David on the west side of the Gihon in the valley to the entrance of the Fish Gate and all around the terrace; he made it much higher. He placed army officers in all the fortified cities in Judah.