A cross rate is the effective exchange rate achieved for two currencies across the US dollar. For example, a cross rate for sterling and French francs, where the customer wishes to sell sterling and buy French francs would be calculated by firstly converting the sterling into dollars and then converting the dollars into French francs. The use of cross rates is to identify potential arbitrage opportunities and to obtain quotes for currencies which are not commonly quoted against each other.
The exchange rate between two currencies expressed as the ratio of two foreign exchange rates that are both expressed in terms of a third currency. Foreign exchange rate between two currencies other than the U.S. dollar, the currency in which most exchanges are usually quoted.
The exchange rates between any two currencies that are considered non-standard in the country where the currency pair is quoted. For example, in the US, a GBP/JPY quote would be considered a cross rate, whereas in the UK or Japan it would be one of the primary currency pairs traded.