Proto-Indo-European *dʰerg-

→ English dark (derived)

→ English terne (root)

→ English terne (derived)

→ Irish dearg (inherited)

→ Scottish Gaelic dearg (derived)

→ Lithuanian dergėti (derived)

→ Old Irish derg (inherited)

→ Tocharian B tarkär (derived)

→ Tocharian A tärkär (derived)