The rate at which a foreign exchange dealer converts one currency into another currency on a particular day is the

Exchange Rate

Explanation:

In finance, an exchange rate is a rate at which a foreign exchange dealer converts one currency into another currency on a particular day. It is also related to the value of one country's currency to another currency.

Exchange rates can be either fixed or floating. Central banks of a country determine the fixed exchange rates and floating exchange rates are determined as a result of market demand and supply.

Spot For-ex Rate

Explanation:

Foreign Exchange Markets are the markets in which currencies are exchanged with each other, at foreign exchange rates.

Spot Exchange Rate is the for-ex rate in case of transactions, which get settled with currencies exchange immediately (or within two business days). So, the rate at which forex dealer actually converts a currency into another currency is the Spot Exchange Rate. It is highly volatile, fluctuates as per currencies demand & supply in forex markets.

This rate is different from Forward Forex rate, which is predetermined agreement based forex rate, for which real currencies exchange take place later on a specified date. It protects people from spot exchange rate volatility