More specifically, it means “The Senate and People of Rome.”

Older millennial here. I know a few random words and phrases in Latin. A couple examples:

“Quis custodiet ipsos custodes?”
“Who will watch the watchmen?”
Thanks to the comic Watchmen. Meaning it is difficult to regulate the actions of people in power.

“Alea iacta est.”
“The die is cast.”
Attributed to Julius Caesar when he crossed the Rubicon river, guaranteeing there would be a civil war. Meaning the outcome is uncertain, but you’ve passed the point of no return (“crossing the Rubicon” is also used to mean that).

I don’t know any ancient Greek though.