Ethereum is a decentralized platform for applications. Applications build on it can use smart contracts - computer algorithms which execute themselves when data is supplied to the platform. There is no need for any human operators.
Ethereum [ETH] is a cryptocurrency with its own blockchain. The most actual price for one Ethereum [ETH] is $239.64. Ethereum is listed on 94 exchanges with a sum of 400 active markets. The 24h volume of [ETH] is $4 317 401 355, while the Ethereum market cap is $26 774 863 688 which ranks it as #2 of all cryptocurrencies. You can find more information about Ethereum [ETH] on ethereum.org