Ethereum is an open-source network powered by blockchain technology that was launched in 2015.
Technically, the currency associated with Ethereum is ether (ETH), although the word Ethereum is increasingly used to refer to both the network and the currency. Ether is used to reward those that run the Ethereum network.
Ethereum is the base off which many other blockchain networks are built, with particular relevance in the fast-growing worlds of DeFi and NFTs, making ether probably the first, and certainly the most influential utility coin.