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 $149.15. Ethereum is listed on 79 Exchanges with a sum of 400 active markets. The 24h volume of [ETH] is $4 795 056 430, while the Ethereum market cap is $16 232 066 327 which ranks it as #2 of all cryptocurrencies. You can find more information about Ethereum [ETH] on ethereum.org