Bimetallism is a monetary system that operated in the United States and the Latin Union (1865-1873) in Europe during the late 18th and 19th centuries.
Under bimetallism, two metals (gold and silver) constituted legal tender, and served as an international standard of value and means of payment.
Bimetallism was preferred also by the Scottish economist Adam Smith (1723-1790). Because, having two precious metals connected to each other in a fixed ratio, which was then referred to as the mint ratio, was relatively more stable.
The bimetallic standard was replaced by the gold standard.
Also see: gold standard