Amboise (Lat. Ambacia). a town on the left bank of the Loire, in the department Indre et Loire, France. The ancient castle, now only used as a state prison, was once the residence of French kings. Charles VIII. was born and died there. The Huguenot conspiracy of Amboise found its beginning and end on this spot (1560). A good trade is done in wine, and woollen and steel goods are manufactured.