SOMMA, a town of the kingdom of Naples, in the province, and 9 miles E. of Naples, at the north foot of Mount Vesuvius. It contains a castle, several churches and monasteries, a college and an hospital. The northern summit of Vesuvius, anciently known as Mons Summanus, is now called Monte Somma. Some trade is carried on at Somma in wine and fruit. Pop. 7000.