Where does “dʰerg-o-s” come from?

dʰerg-o-s (Proto-Indo-European) comes from Proto-Indo-European dʰerg-, from Proto-Indo-European dʰer- — to support; to hold.

Ancestry of “dʰerg-o-s”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	dʰerg-	to dim, darken; dim, dull; dark, dusky
2	Proto-Indo-European	dʰer-	to support; to hold

dʰerg-o-s — Etymology, Origin & Word History | Etymology Explorer