Old Irish bráthair

← Proto-Celtic *brātīr (inherited)

← Proto-Indo-European *bʰréh₂tēr (inherited)

→ Old English broþor (cognate)

→ Irish deartháir (mention)

→ Irish bráthair (inherited)

→ Scottish Gaelic bràthair (inherited)

→ Manx braar (inherited)

→ Manx jarroo-vraar (mention)

→ Old Irish derbráthair (prefix)

→ Old Irish bráthardae (suffix)

→ Old Irish sinserbráthair (compound)