Where does “grob” come from?
grob (Lower Sorbian) comes from Proto-Slavic grǫbъ, from Proto-Slavic grěti, from Proto-Indo-European gʷʰer-, from Proto-Indo-European gʷʰe-gʷʰór-e ~ gʷʰe-gʷʰr-ḗr.
grob (Lower Sorbian): ditch
Ancestry of “grob”, step by step