Smart contract

Code deployed on a blockchain that executes automatically when called.

A smart contract is a program deployed on a blockchain whose code executes deterministically when called by a transaction. Once deployed, the code is public, immutable (unless upgradable), and runs without any operator. Ethereum's EVM popularized general-purpose smart contracts; Solana, Move chains, and others now compete in this space.

"Smart contract" is a slight misnomer — contracts in the legal sense involve enforceable obligations between parties, while smart contracts are simply code. The name has stuck despite the imprecision.