What is Ethereum?

From a computer science perspective, Ethereum is a deterministic but practically unbounded state machine, consisting of a globally accessible singleton state and a virtual machine that applies changes to that state.

From a more practical perspective, Ethereum is an open source, globally decentralized computing infrastructure that executes programs called smart contracts. It uses a block chain to synchronize and store the systems’s state changes, along with a cryptocurrency called ether to meter and constrain execution resource costs.

Compared to Bitcoin

purpose : ether is intended as a utility currency to pay for use of the Ethereum platforms as the world computer.

Ethereum is designed to be a general purpose programmable blockchain that runs a virtual machine capable of executing code of arbitrary and unbounded complexity.

Where Bitcoin’s Script language is, intentionally, constrained to simple true/false evaluation of spending conditions, Ethereum’s language is Turing complete, meaning that Ethereum can straightforwardly function as a general-purpose computer.