Ethereum is a decentralized, blockchain-based platform that allows anyone to build and execute decentralized applications (DAPPs).
Simply put, Ethereum lets people build apps on the blockchain for purposes beyond payments. The Ethereum blockchain connects thousands of computers around the world and forms a massive world computer that anyone can access, build, and execute programs on.
To operate or execute programs on Ethereum, you would need to pay with Ether (ETH). Although it is sometimes referred to as a “cryptocurrency”, Ether is not intended to be a currency per se. It is more accurate to say that it is the digital “fuel” required to run tasks and transactions on the Ethereum network.