Money functions as a medium of exchange by eliminating the need for a coincidence of wants.

Medium of Exchange

Any item sellers generally accept and buyers generally use to pay for a good or service; money; a convenient means of exchanging goods and services without engaging in barter.

Coincidence of Wants

A situation in barter economies where two parties each possess goods or services that the other desires, enabling a direct exchange without the need for a common medium of trade.