Czech trn

← German Dorn (cognate)

← English thorn (cognate)

← Russian тёрн (cognate)

← Serbo-Croatian tȓn (cognate)

← Slovak tŕň (cognate)

← Proto-Slavic *tьrnъ (inherited)

→ Czech trnka (affix)

→ Russian тёрн (cognate)

→ Serbo-Croatian trn (cognate)