Where does “écrivaine” come from?

écrivaine (French) comes from French écrivain, from Old French escrivain, from Vulgar Latin scriba, from Latin scriba, from Latin -a, from Proto-Italic -ā, from Proto-Indo-European -éh₂.

Ancestry of “écrivaine”, step by step

Step	Language	Word	Meaning
1	French	écrivain	writer
2	Old French	escrivain	writer
3	Vulgar Latin	scriba	—
4	Latin	scriba	writer, scribe, secretary, clerk
5	Latin	-a	suffixed to the roots of verbs, forms agent...
6	Proto-Italic	-ā	Forms masculine agent nouns from prefixed or compounded bases
7	Proto-Indo-European	-éh₂	—

Every word from Proto-Indo-European -éh₂ →Every word from Latin -a →Every word from Latin scriba →