demonetization n. The act of demonetizing, or the condition of being demonetized; specificially, The declaration by a government that something (e.g. gold or silver) is no longer the legal tender of a country; as, the demonetization of gold.
... the 412-1/2 grains in the dollar were worth $1.02 in gold money. The silver dollar was worth more as silver bullion than as money, and was therefore little used as money. This dropping of the silver dollar from the list of coins, or ceasing to coin it, was called the "demonetization of silver." ... — A Brief History of the United States • John Bach McMaster