What is the term for an increase in the value of a currency in a fixed exchange rate system?

In a fixed exchange rate system, when the value of a currency increases relative to other currencies, the correct term to describe this action is revaluation. A revaluation occurs when a country's central bank or government decides to raise the value of its currency officially, which is distinct from other concepts like depreciation or devaluation.

To clarify, depreciation refers to a decrease in the value of a currency due to market forces, which is not applicable in a fixed exchange rate system since such currencies are not allowed to fluctuate freely based on supply and demand. Devaluation involves a government or central bank intentionally lowering the currency value, which again does not align with an increase in value. Appreciation is typically used in the context of floating exchange rates to describe an increase in value as determined by market forces, rather than an official change in policy. Thus, revaluation is the specific action taken by authorities in a fixed exchange rate scenario to increase a currency's value.