Where does “omnibus” come from?

omnibus (Dutch) comes from Latin omnibus, from Latin omnis, from Proto-Italic opnis, from Proto-Indo-European h₃ep-ni-s, from Proto-Indo-European h₃ep- — to work, toil, make; ability, force.

Ancestry of “omnibus”, step by step

Step	Language	Word	Meaning
1	Latin	omnibus	dative masculine plural of omnis; dative feminine...
2	Latin	omnis	every; all
3	Proto-Italic	opnis	every, all
4	Proto-Indo-European	h₃ep-ni-s	working
5	Proto-Indo-European	h₃ep-	to work, toil, make; ability, force

Every word from Proto-Indo-European h₃ep- →Every word from Proto-Indo-European h₃ep-ni-s →Every word from Proto-Italic opnis →