CHALCIDICUM, or CHALCEDONIUM, in the ancient architecture, a large magnificent hall belonging to a tribunal or court of justice. Petrus 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 ἐκκατάστημα, brafis, and δικαίωμα, justice. Others say, the money was struck in it; and derive the word from ἐκκατάστημα, and ὀξύς, boye. 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.