The Ethereum Network is fuelled by a "virtual token" called Ether.
Ether is required to pay the Ethereum network in order to execute any Smart Contracts and hence, has an intrinsic value. Ether can be traded for fiat money and even accepted as a form of payment as a result. This aspect of Ethereum has an ever-increasing number of people trading Ether Tokens as a form of currency earning it the label of being a Cryptocurrency.
Please note that it is commonplace to label or simply identify Ether Tokens as Ethereum. There is no right or wrong here, however, kindly note that the when you purchase any coins you are purchasing the Ether Tokens.
If you wish to find out more about Ethereum, you can read its Whitepaper here.