Boyd’s Bible Dictionary:
(flock). A tower (Gen. 35:21).
Concise Bible Dictionary:
This occurs only in Genesis 35:21, and signifies “Tower of the flock.” Probably a tower built by the shepherds for the protection of their flocks. It was apparently a little south of Bethlehem. Jacob halted there with his flocks. The expression “tower of the flock” occurs in Micah 4:8 (Edar in the margin) as the stronghold of the daughter of Zion.