Where does “róść” come from?

róść (Old Polish) comes from Proto-Slavic orsti, from Proto-Indo-European h₃ér-.

Ancestry of “róść”, step by step

Step	Language	Word	Meaning
1	Proto-Slavic	orsti	to grow
2	Proto-Indo-European	h₃ér-	—

róść — Etymology, Origin & Word History | Etymology Explorer