Money:

Money, as defined in economics, is anything that is readily and widely accepted as a medium for the exchange for goods and services or in settlement of debts. Money plays a crucial role in the economic system of any country. It is a means for promoting specialization and exchange on which modern economic activity is based.

Before the invention of modern money in the forms of currency notes and coins as we know today, trade had been conducted by barter, through the use of commodity monies such as cowries shells, cow, manilas, iron bars, etc. The barter system refers to a situation where goods are directly exchanged for goods.