Ethereum is an open source, public, blockchain-based distributed computing platform and operating system featuring smart contract (scripting) functionality. It supports a modified version of Nakamoto consensus via transaction-based state transitions.
Ether is the cryptocurrency generated by the Ethereum platform as a reward to mining nodes for computations performed and is the only currency accepted in the payment of transaction fees.[1]
Ethereum provides a decentralized virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes.[2] The virtual machine’s instruction set, in contrast to others like Bitcoin Script, is Turing-complete. “Gas”, an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.[2]