We look at the functions of money. Firstly it's a medium of exchange, so it's some commodity which facilitates the exchange of goods and services.
It is also a unit of account, which means that we use money to reckon prices and reckon values for comparisons between goods and services or over time.
And thirdly, money is a store of value. It is an asset. It's something that we can use to store value away to be retrieved at a later point in time. So we can not consume today, we can hold money instead - and transfer that consumption power to some point in the future.
In the earliest days, for example in ancient Babylon, measures of wheat were the money commodity. People would exchange other goods and services firstly by exchanging quantities of wheat. And eventually it was worked out by the Babylonian priests that they could hold the wheat in a central store and then simply keep records of who owned the wheat. And rather than physically moving the wheat around, eventually we had a primitive system - quite advanced by the terms of the day - of record keeping. We had ledgers.
1.Medium of exchange 交换媒介
2.Unit of account 计算单位
3.Store of value 价值储存手段
4 money commodity 商品货币，实物货币
5 primitive system of record keeping 原始簿记制度
6 ledger 分户账 转