In very ancient times, that is, in the Rg Vedic period, civilization was very backward. In that age there was no such thing as buying and selling in the strict sense of the term. The system of exchange that was in vogue in those days can best be called “barter”. For instance, people used to give some barley to someone (in those days people were not acquainted with wheat or rice). In exchange they would get a container. Again, in exchange for a sieve, someone would get some lentils. (In those days people were not acquainted with cow pea. They were more acquainted with legumes than with Bengal grams.) We can surmise that this system of exchange continued for a long time.

Later, people began to feel some practical inconvenience because they were often not able to get the items they badly needed, and there was no ready market to sell the commodities that people produced. Under the circumstances, people converted the commodities for exchange into some kind of standard wealth to be used as needed. Thus, they began to think of media of exchange.

In India, the first medium of exchange used was sea shells. These sea shells were the first coins. The most ancient root verb for the exchange of commodities was krii, conjugated as kriińiite. But when sea shells were first introduced as the medium of exchange, people felt the need to distinguish this new type of transaction from ordinary barter transactions. So when a transaction would be effected through an exchange of commodities, the root verb krii (with the conjugation kriińiite) continued to be used. But when a transaction would be effected through the medium of sea shells – the system known today in English as “buying” (“to purchase” can mean to get something through barter, but “to buy” can only mean to get something with money) – though the same root verb was used, it was conjugated as kriińáte. Thus, towards the end of the Vedic Age the root verb krii became ubhayapadii, conjugated in both the above ways. Páńini, the first grammarian in the world, recognized the word ubhayapadii. Later grammarians followed his lead.

From the Gupta Age onwards barter trade between different countries continued, but in towns and cities it was greatly reduced, while the buying and selling of commodities with money greatly increased. The use of metal coins began to replace sea shells as media in an improved system of exchange. Much later still, paper notes were introduced in China. Since the Gupta Age, buying and selling has mostly been undertaken through monetary exchange.

The Sanskrit word mudrá became “token” in English, meaning “something which is represented by a medium”. The inner meaning of the word “coin” is also token.