Old Irish béim

← Breton boem (cognate)

← Proto-Celtic *bēsman (inherited)

← Proto-Indo-European *bʰeyh₂- (root)

← Proto-Indo-European *bʰeyh₂- (derived)

← Proto-Indo-European *-mn̥ (mention)

← Cornish bom (cognate)

← Old Irish benaid (mention)

→ Irish béim (inherited)