中文：

货币是一种交换媒介，是经济活动中不可或缺的一部分。随着社会的发展，货币的形式和种类也在不断变化。那么，到底什么是货币呢？

从最基本的意义上来说，货币是一种能够充当交换媒介的商品。它必须具有普遍接受性和价值储藏的功能。普遍接受性是指货币在交换中能够被普遍接受，无论是购买商品还是支付服务。价值储藏是指货币必须能够被用来积累财富，并在未来能够以相同的价值进行交换。

从历史上看，货币的形式多种多样。例如，贝壳、铜器、黄金、白银、纸币等都曾经充当过货币。然而，随着科技的发展，现代货币已经不再是具体的商品，而是一种基于国家信用和法定地位的货币符号。

英文：

Currency is a medium of exchange that is indispensable in economic activities. With the development of society, the forms and types of currency are constantly changing. So, what is currency?

In the most basic sense, currency is a commodity that can act as a medium of exchange. It must have the function of universal acceptance and store of value. Universal acceptance means that currency can be universally accepted in exchange, whether it is used to purchase goods or pay for services. Store of value refers to currency must be able to be used to accumulate wealth and can be exchanged with the same value in the future.

Historically, currency has come in many forms. For example, shells, copper vessels, gold, silver, paper money have all served as currency. However, with the development of technology, modern currency is no longer a specific commodity, but rather a monetary symbol based on national credit and legal status.