Where does “-at” come from?

-at (French) comes from Latin -ātus, from Proto-Italic -ātos, from Proto-Indo-European -éh₂tos.

-at (French): "A suffix denoting the third-person singular...

Definitions

Step	Language	Word	Meaning
1	Latin	-ātus	—
2	Proto-Italic	-ātos	—
3	Proto-Indo-European	-éh₂tos	—

-at — Etymology, Origin & Word History | Etymology Explorer