1)
What is "Beis Milo"?
1.
Rashi: It is a place. Radak- since it says "ha'Yored Sila", it seems that there was another Beis Milo 1 [so the Navi needed to identify which one].
1
Malbim: The other is in Shoftim (9:6); it is near Shechem. This one was near Yerushalayim.
2)
What is "Sila"?
1.
Rashi: It is a place.