What is the meaning of "Iyei ha'Avarim"?
Rashi and Rashbam: It means 'desolate passes' 1 via which one crossed over Har N'vo to enter Eretz Cana'an.
Targum Onkelos and Targum Yonasan: It means the desolate plains.
Rashi: Iy (of which only the 'Ayin' is a root letter means a ruin, and Rashi ddoes not know why the Torah refers to the passes ain this way.
Where were these passes situated?
Rashi: They were situated on the east side of Mo'av, on a strip of land that jutted out from the Emori that bordered the River Arnon.