Chalcidicum, or Chalcedonium, in the ancient architecture, a large magnificent hall belonging to a tribunal or court of justice. Festus says, it took its name from the city Chalcis; but he does not give the reason. Philander will have it to be the court or tribunal where affairs of money and coinage were regulated; so called from χαλκός, brass, and ἔκοινος, justice. Others say, the money was struck in it; and derive the word from χαλκός, and στοά, house. In Vitruvius, it is used for the auditory of a basilica: in others of the ancient writers for a hall or apartment where the heathens imagined their gods to eat.