'Gap' in the Bible

This [is] the reason that he rebelled against the king: [when] Solomon built the Millo, he closed the gap of the city of David his father.

Now when it was reported to Sanballat, Tobiah, Geshem the Arab, and to the rest of our enemies that I had built the wall and that no gap was left in it--though up to that time I had not erected doors in the gates--