A floating exchange rate or fluctuating exchange rate is a type of exchange rate regime wherein a currency's value is allowed to freely fluctuate according to the foreign exchange market.
A fixed exchange-rate system (also known as pegged exchange rate system) is a currency system in which governments try to maintain their currency value constant against a specific currency or good.
Pegged floating currencies are pegged to some band or value, either fixed or periodically adjusted. These are a hybrid of fixed and floating regimes.