Where does “ostiaire” come from?

ostiaire (French) comes from Latin ostiārius, from Latin -ārius, from Proto-Italic *-āzios.

ostiaire (French): porter, doorman, ostiary

Definitions

Step	Language	Word	Meaning
1	Latin	ostiārius	—
2	Latin	-ārius	—
3	Proto-Italic	*-āzios	—

ostiaire — Etymology, Origin & Word History | Etymology Explorer