billon
/ˈbɪlən
/noun [mass noun]
An alloy formerly used for coinage, containing gold or silver with a predominating amount of copper or other base metal.The falling value of the Scottish currency derived in part from the practice of mixing silver with alloy to produce the base metal billon....
- Large quantities of billon coins were produced in the Roman era, many with a silver wash, and in mediaeval times throughout Europe.
- Numismatists of the 19th century, realizing the problems caused by the gaps in their knowledge, invented an arbitrary scale to refer to the bronze and billon coins of the period.
Origin
Early 18th century: from French, literally 'bronze or copper money', in Old French 'ingot', from bille (see billet2).