An item that buyers will exchange with a seller when they want to purchase goods or services to avoid the inefficiencies of a barter trade system. This is one of the three main functions of money alongside a unit of account and store of value, to ensure an efficient and successful monetary system.
Below is an illustration of how the invention of a monetary system facilitates a medium of exchange for money (which has no intrinsic value) for goods of perceived equal value. In all advanced economies money is universally accepted as an acceptable means of payment and therefore transactions like this one below occur millions of time during the day.
