Where does “фойе” come from?

фойе (Russian) comes from French foyer, from Vulgar Latin focarium, from Latin focārius, from Latin -ārius, from Proto-Italic *-āzios.

Ancestry of “фойе”, step by step

Step	Language	Word	Meaning
1	French	foyer	hearth; lobby, foyer; home, domicile
2	Vulgar Latin	focarium	—
3	Latin	focārius	—
4	Latin	-ārius	—
5	Proto-Italic	*-āzios	—

фойе — Etymology, Origin & Word History | Etymology Explorer