CHALCIDICUM, or CHALCEDONIUM, in the ancient architecture, a large magnificent hall belonging to a tribunal or court of justice.—Fetus 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 \(\chi\alpha\lambda\alpha\kappa\iota\sigma\) bras, and \(\iota\eta\eta\) justice. Others say, the money was struck in it; and derive the word from \(\chi\alpha\lambda\alpha\kappa\iota\sigma\), and \(\iota\eta\eta\), house. In Vitruvius, it is used for the auditory of a basilica; in other of the ancient writers for a hall or apartment where the heathens imagined their gods to eat.