BOSA, a city on the western coast of the island of Sardinia, in the province of Cagliari and district of Oristano, in a fine valley on the northern bank of the Terno, in 40° 16' 40" N. lat. and 8° 25’ 31" E. long. It is the. see of a bishop, and has a cathedral and a diocesan seminary. The harbour is safe, being sheltered by an islet. Coral fishery is carried on, and there is trade in cheese, grain, and wine. Population, 6706.