Where does “сенат” come from?

сенат (Russian) comes from Latin senātus, from Latin -ātus, from Proto-Italic -ātos, from Proto-Indo-European -éh₂tos.

сенат (Russian): senate

Definitions

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

сенат — Etymology, Origin & Word History | Etymology Explorer