fiscus, in the civil law, the treasury of a prince, or state; or that to which all things due to the public do fall. The word is derived from the Greek θήσαυρος, a great basket, used when they went to market.—By the civil law, none but a sovereign prince has a right to have a fisc or public treasury.

At Rome, under the emperors, the term aerarium was used for the revenues destined for support of the charges of the empire; and fiscus for those of the emperor's own family. The treasury, in effect, belonged to the people, and the fiscus to the prince.