Rashi on Genesis 14:6/רש"י על בראשית י״ד:ו׳

1בהררם means IN THEIR MOUNT (i. e.הרר is a form of הר — really an earlier form — with pronominal suffix ָ מ ;cf. הררי קדש etc.)

2איל פארן EL-PARAN — As it is translated in the Targum: Plain of Paran. But I hold that איל does not signify a plain in general but that the lowland of Paran bore the name of El, and that of Mamre was named Elone; that of the Jordan was called Kikkar, whilst that of Shittim was called Abel — Abel-Shittim — and so, too, the lowland of [Baal] Gad was named Baal. All these are translated in the Targum by מישור, but each really had its own particular name.

3על המדבר BY THE WILDERNESS — next to the wilderness; a similar use of על is (Numbers 2:20) “and next unto him (עליו) shall be the tribe of Manasseh’’.