a United States dollar that has been deposited outside the United States, especially in Europe. Foreign banks holding Eurodollars are obligated to pay in U.S. dollars when the deposits are withdrawn. Dollars form the largest component of all currencies in which such deposits are held and which are generally known as Eurocurrency. The name originated in the early 1960s when eastern European countries wishing to hold dollar deposits outside the United States deposited them in European banks. Later the market involved many non-European countries.

By accepting a Eurodollar deposit, a bank actually receives a balance with a United States bank. The receiving bank is then able to make dollar loans to customers. Most such loans are used to finance trade, but many central banks also operate in the market.