Swansea (swŏnˈzē) [key], town (1990 est. pop. 15,500), Bristol co., SE Mass., a suburb of Fall River, on an inlet of Mount Hope Bay; founded 1667, inc. 1785. Once a vast farmland, it has become chiefly residential. Many of its inhabitants were massacred in King Philip's War (1675), but the town was later rebuilt and prospered.