What is an act of trading goods or services between two or more parties without the use of money called?

In trade, barter is a system of exchange in which participants in a transaction directly exchange goods or services for other goods or services without using a medium of exchange, such as money.

Since direct barter does not require payment in money, it can be utilized when money is in short supply, when there is little information about the credit worthiness of trade partners, or when there is a lack of trust between those trading.

Barter is an option to those who cannot afford to store their small supply of wealth in money, especially in hyperinflation situations where money devalues quickly.

Adam Smith, the father of modern economics, sought to demonstrate that markets (and economies) pre-existed the state. He argued (against conventional wisdom) that money was not the creation of governments. Markets emerged, in his view, out of the division of labor, by which individuals began to specialize in specific crafts and hence had to depend on others for subsistence goods. These goods were first exchanged by barter.