Barr- is a pre-Indo-European linguistic root meaning 'wooded hill', 'natural barrier'.[1]
In addition to the common noun bar, it explains many place names as:
but not Le Bar-sur-Loup, a former Albarn > Aubarn.
In Alps, the word applies to rocky escarpments:
This root should not be mistaken for the Basque root Bar- / ibar 'valley'.