Where does “octante et un” come from?

octante et un (French) comes from French un, from Middle French un, from Old French un, from Latin ūnus, from Old Latin oinos, from Proto-Italic oinos, from Proto-Indo-European óynos — one; single.

octante et un (French): eighty-one

Definitions

eighty-one

Ancestry of “octante et un”, step by step

octante et un traces back through 3 separate lines of ancestry.

via French un

Step	Language	Word	Meaning
1	French	un	an, a; one
2	Middle French	un	a, an; one
3	Old French	un	a, an; one
4	Latin	ūnus	one, single
5	Old Latin	oinos	one
6	Proto-Italic	oinos	cardinal number 1 Previous: n/a Next: *duō;...
7	Proto-Indo-European	óynos	one; single

via French et

Step	Language	Word	Meaning
1	French	et	and
2	Middle French	et	and
3	Old French	et	and
4	Latin	et	and; plus; though, even if
5	Proto-Indo-European	éti	beyond; over
6	Proto-Indo-European	h₁é	and, then
7	Proto-Indo-European	ǵʰe	Postpositional intensifying particle: indeed, at any rate, in fact

via French octante

Step	Language	Word	Meaning
1	French	octante	eighty
2	Latin	octōgintā	eighty; 80
3	Proto-Indo-European	oḱtódḱomt	eighty
4	Proto-Indo-European	oḱto(w)-dḱomt	eight-ten

Every word from Proto-Indo-European óynos →