Aspron

The aspron (Greek:ἄσπρον), from Latin asper, was a late Byzantine name for silver or silver-alloy coins.

The Latin word asper originally meant "rough", but had gradually acquired the connotation of "fresh" and, especially when referring to silver, "white", by the imperial period. It acquired a technical meaning in the 12th century, when the Byzantines began to refer to the billon trachy coin, which was issued in a blanched state, as aspron. The same name was also sometimes applied to the contemporary electrum trachy as well.