Certificate requiring the issuer to pay a certain sum of money on demand to a specific person or organization. Money orders provide a fast, safe, and convenient means of transferring small sums of money. They are issued by governments (usually through postal authorities), banks, and other qualified institutions to buyers who pay the issuer the face amount of the money order plus a service charge. Because they are exchangeable for cash on demand, they are a generally accepted means of payment. The American Express Co. began issuing money orders in 1882; the company also created the first traveler's checks nine years later. See alsocurrency.