Where does “quorum” come from?

quorum (Latin) comes from Proto-Italic kʷoi, from Proto-Indo-European kʷós — who.

Ancestry of “quorum”, step by step

Step	Language	Word	Meaning
1	Proto-Italic	kʷoi	who, what
2	Proto-Indo-European	kʷós	who

quorum — Etymology, Origin & Word History | Etymology Explorer