Русско-англо-русский юридический словарь

In macroeconomics and modern monetary policy, a devaluation is an official lowering of the value of a country's currency within a fixed exchange-rate system, in which a monetary authority formally sets a lower exchange rate of the national currency in relation to a foreign reference currency or currency basket. (Wikipedia)

‘a financial crisis will result in severe devaluation of the country's currency’ (Oxford Dictionary)