*bhergh- (2) Look up *bhergh- (2) at Dictionary.com
Proto-Indo-European root meaning "high," with derivatives referring to hills and hill-forts.

It forms all or part of: barrow (n.2) "mound, hill, grave-mound;" belfry; borough; bourgeoisie; burg; burgess; burgher; burglar; faubourg; iceberg.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit b'rhant "high," brmhati "strengthens, elevates;" Avestan brzant- "high," Old Persian bard- "be high;" Greek Pergamos, name of the citadel of Troy; Old Church Slavonic bregu "mountain, height;" Old Irish brigh "mountain;" Welsh bera "stack, pyramid."