Where does “храст” come from?

храст (Bulgarian) comes from Proto-Slavic xvorstъ, from Proto-Balto-Slavic kšwáršta, from Proto-Indo-European (s)kworstom.

храст (Bulgarian): bush, frutex, shrub

Definitions

Step	Language	Word	Meaning
1	Proto-Slavic	xvorstъ	brushwood
2	Proto-Balto-Slavic	kšwáršta
3	Proto-Indo-European	(s)kworstom	—

храст — Etymology, Origin & Word History | Etymology Explorer