Ses'ter-tĭus, n.

n. [L. sestertius, Sp. sestercio, It. sesterzio, Lat. sestertius (se, semis), from semis-tertius, two and a half, from semis, half, and tertius, third.] (Rom. Antiq.) A Roman coin or denomination of money, in value the fourth part of a denarius, and originally containing two asses and a half, afterward four asses; — equal to about two pence sterling, or four cents.

The sestertium was equivalent to one thousand sestertii, equal to £5 11s. 1d. sterling, or about $48, before the reign of Augustus. After his reign it was valued at £7 10s. 1d. sterling. It was originally coined only in silver, but afterward both in silver and brass.