In what way does a medium of exchange differ from a barter system?

A medium of exchange is a universally accepted item, such as currency, that facilitates trade by providing a standard measure of value. In contrast, a barter system relies on the direct exchange of goods and services without a standardized medium, which can lead to inefficiencies due to the need for a double coincidence of wants. This means that both parties must want what the other offers, making transactions more complex. Overall, a medium of exchange simplifies trade and enhances economic efficiency.