**Blockchain** is a decentralized, distributed digital ledger that records transactions across a network of computers in a secure, transparent, and tamper-resistant way. Each transaction is grouped into a "block," cryptographically linked to the previous one, forming an immutable chain. Once added, data cannot be altered without changing all subsequent blocks and gaining network consensus.

This technology eliminates the need for central authorities like banks or intermediaries, enabling trustless peer-to-peer interactions. Beyond cryptocurrencies like Bitcoin, blockchain powers smart contracts, supply chain tracking, digital identity, decentralized finance (DeFi), NFTs, and secure voting systems. Its core strengths—transparency, security, and immutability—continue to drive innovation across industries.