part of the Mediterranean Sea off the western coast of Italy
The Tyrrhenian Sea (Italian: Mar Tirreno) is part of the Mediterranean Sea.
The sea touches the borders of these regions: Corsica and Sardinia (west), Tuscany, Lazio, Campania, Basilicata, and Calabria (east), and Sicily (south).
Its name derives from the Greek name for the Etruscans.
In the Third and Second centuries BC the Romans called it "Mare Nostrum".