Ethereum (ETH) is a decentralized, open-source blockchain platform that enables developers to build decentralized applications (dApps) and smart contracts. It was created by Vitalik Buterin in 2013 and launched in 2015. Ethereum is the second-largest cryptocurrency by market capitalization after Bitcoin.

One of the key features of Ethereum is its ability to execute smart contracts, which are self-executing contracts with the terms of the agreement between buyer and seller being directly written into lines of code. This eliminates the need for intermediaries and reduces the risk of fraud. Ethereum also allows developers to create their own tokens, which can be used for a variety of purposes such as fundraising, rewards, and governance. The Ethereum network is powered by its native cryptocurrency, Ether (ETH), which is used to pay for transaction fees and computational services on the network.