Regio (pl. regiones) is the Latin word for ‘region’ and the Italian word for ‘royal’ It may refer to: Regiopolis, a concept for urban centers in between metropolitan areas. Ancient toponymy Regiones of Augustan Italy, the departments in which Roman Emperor Augustus divided Italy. 14 regions of the Augustan Rome, in ancient Rome as a name for quartiers of the city of Rome 14 regions of Medieval Rome, resulting from the redivision of the Rome after the revolution of 1143 Regio, in ancient Constantinople as a name for the 14 quarters of the city of Constantinople, defined in analogy with those of Rome Regio Aromatica, name for the Horn of Africa Regiones, administrative subdivisions of the kingdoms of Anglo-Saxon England Astronomy Regio (astronomy), which, in planetary geology, is a large area of a planet or moon that is strongly differentiated in colour or albedo A regio of Venus: Alpha Regio Asteria Regio Beta Regio Ovda Regio A regio of Pluto: Cthulhu Regio Lowell Regio Tombaugh Regio A regio of Titan: Tui Regio A regio of Ganymede: Galileo Regio A regio on Phoebe: Leto Regio A regio on Iapetus: Cassini Regio See also Regio Ducal, a former opera house in Milan Teatro Regio (disambiguation), several theaters in Italy Regio Esercito, the army of the Kingdom of Italy Regia Marina, the navy of the Kingdom of Italy Regio Esercito (World War II) The Stadler Regio-Shuttle, a German diesel railcar Regio Trans, a Romanian railway company Regio (Swiss railway train), a category of train service in Switzerland