Old Irish trí

← Proto-Celtic *trīs (inherited)

← Proto-Indo-European *tréyes (inherited)

→ Irish trí (inherited)

→ Irish tréimhse (mention)

→ Irish tríú (mention)

→ Scottish Gaelic trì (inherited)

→ Manx tree (inherited)

→ Manx treeoo (mention)

→ Old Irish treise (mention)

→ Old Irish trédae (mention)