Millo in Smiths Bible Dictionary

(a rampart, mound) a place in ancient Jerusalem. Both name and place seem to have been already in existence when the city was taken from the Jebusites by David. 2Sa 5:9; 1Ch 11:8 Its repair or restoration was one of the great works for which Solomon raised his "levy," 1Ki 9:15,24; 11:27 and it formed a prominent part of the fortifications by which Hezekiah prepared for the approach of the Assyrians. 2Ch 32:5 The last passage seems to show that "the Milo" was part of the "city of David," that is, of Zion. Comp. 2Ki 12:20