sestertius

This form had its origin in the sale of goods by weight, but was gradually extended to all sales; and the practice was for the buyer to strike the balance with a piece of money called a sestertius, which was immediately paid over to the vendor as part of the price; and hence the expression per æs et libram vendere.

The sestertius was worth from four to five cents.

Sestertius was a silver coin, stamped on one side with Castor and Pollux, and on the opposite with the city.

Those in most frequent use, were the As, Sestertius, Victoriatus, Denarius, Aureus.

Second—If a numeral adjective, of a different case, were joined to the genitive plural of Sestertius, it signified so many thousand Sesterces; as decem Sestertium, 10,000 Sesterces—$357.