Where does “primigenous” come from?

primigenous (English) comes from Latin primigenus, from Latin prīmus, from Latin prīsmos, from Proto-Italic priisemos, from Proto-Indo-European per-, from Proto-Indo-European pr̥tós — passed , crossed.

primigenous (English): First formed or generated; original; primigenial

Definitions

First formed or generated; original; primigenial

Ancestry of “primigenous”, step by step

Step	Language	Word	Meaning
1	Latin	primigenus	original
2	Latin	prīmus	—
3	Latin	prīsmos	—
4	Proto-Italic	priisemos	foremost, first
5	Proto-Indo-European	per-	before, in front; first; to go through
6	Proto-Indo-European	pr̥tós	passed , crossed

Every word from Proto-Indo-European pr̥tós →Every word from Proto-Indo-European per- →Every word from Proto-Italic priisemos →