or Aost, a town of Italy, in Piedmont, and capital of the duchy of the same name, a bishop's see, and subject to the king of Sardinia. It is remarkable for several monuments of the Romans, and for the birth of Anselm archbishop of Canterbury. It is seated at the foot of the Alps, on the river Doria, E. Long. 7° 33'. N. Lat. 45° 38'.