Ariano, a town of southern Italy, in the province of Principato Ultra, 15 m. E. N. E. of Benevento; pop. about 12,000. It is built upon a steep hill, in one of the most frequented passes of the Apennines, and many of the poorer dwellings are dug into the rock and earth. It contains a fine cathedral, numerous churches and convents, several monts de piete, and an academy. This town has frequently been visited by terrible earthquakes, the last of which happened in 1732.