The Ramatis system was an inhabited star system.
In the year 2365, the USS Enterprise-D was diverted to Ramatis III in order to transport Riva, a famous mediator, from his homeworld to Solais V where he would negotiate for an end to a centuries long planetary conflict. (TNG: "Loud As A Whisper")
"RAH-mah-tis." was the pronunciation for this system's name from the script pronunciation guide.