Bartering is a system of trade where participants exchange goods or services directly for other goods or services, without a medium of exchange like money. It is one of the earliest forms of economic exchange, predating the invention of money, and can occur on a bilateral basis (between two parties) or multilateral basis through trade exchanges. Silent trade, or "dumb barter," is a method where traders exchange goods without speaking, often used historically between groups that did not share a common language.