Rashi on Numbers 21:11/רש"י על במדבר כ״א:י״א

1בעיי העברים IN IJE-ABARIM (in the עיים of Abarim) — I do not know why the name (that of these places) was called עיים, for the term עי signifies ruins; it is a thing (spot) that has been swept as it were with a broom. Only the single letter ע in it belongs to the root; it is connected in meaning with יעים (Exodus 27:3) and (Isaiah 28:17) “And the hail shall sweep away (יעה).

2העברים (from עבר to pass) — the road forming a pass for those who at that spot pass by Mount Nebo on their way to the land of Canaan, which mount separates the land of Moab from the land of the Amorites. ...

3על פני מואב ממזרח השמש [IN THE WILDERNESS WHICH IS] BEFORE MOAB TOWARDS THE SUN-RISING (the East) — i.e., to the East of the land of Moab (not in the East of the world).