Chainlink is a decentralized oracle network that connects smart contracts on blockchain platforms with real-world data. It allows these contracts to access external information, such as market prices or weather data, which is essential for executing automated agreements accurately. By using a network of independent nodes, Chainlink ensures that the data provided is reliable and tamper-proof. This enhances the functionality of decentralized applications (dApps) and enables a wide range of use cases, from finance to supply chain management, making it a crucial component in the blockchain ecosystem.