Blockchain signifies a decentralized and distributed ledger technology that securely records transactions across multiple computers. It consists of a chain of blocks, each containing transaction data and linked through cryptographic hashes. This technology ensures transparency and immutability, making it extremely difficult to alter information once recorded. Originally developed for cryptocurrencies, blockchain has expanded to applications in various sectors, including supply chain management, finance, and health records. Its decentralized nature enhances security, trust, and traceability in data management.