Polkadot is a decentralized blockchain protocol designed to connect multiple blockchains into a unified network, enabling cross-chain transfers of data and assets. Founded by Gavin Wood, co-founder of Ethereum, Polkadot uses a relay chain to coordinate consensus and communication among various parachains. Its architecture aims to improve scalability, security, and innovation in the blockchain ecosystem, making it a key player in the development of Web3 infrastructure.