Definition of Fiscus
Roman law. The treasury of the prince or emperor, as distinguished from "serarium,” which was the treasury of the state. This distinction was not observed in France. In course of time the fiscus absorbed the ararium and became the treasury of the state. The treasury or property of the state, as distinguished from the private property of the sovereign.
English law. The king’s treasury, as the repository of forfeited property. The treasury of a noble, or of any private person.
That's the definition of Fiscus in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.