Biella (byĕlˈlä) [key], city (1991 pop. 48,324), Piedmont, NW Italy. It is a major cotton and wool textile manufacturing center. Biella came under the Visconti of Milan in 1353 and under the house of Savoy in 1379. Of note are several palaces (15th–16th cent.), an early Romanesque baptistery (10th cent.), and a Renaissance cathedral.