The Ethereum Virtual Machine (EVM) is the deterministic execution environment used to run smart contracts. A smart contract is code deployed on-chain that can read contract state and change it through transactions. The EVM defines: (1) the exact instruction set (opcodes), (2) the memory and storage model, and (3) the gas accounting rules. Determinism is essential: all full nodes must execute the same transaction and obtain the same resulting state.
From transaction to execution