Blockchain is a decentralized digital ledger technology that records transactions across multiple computers in a way that prevents alteration or tampering. Each record, called a "block," contains a list of transactions, and blocks are linked together in chronological order to form a "chain." Blockchain is often used as the underlying technology for cryptocurrencies, but it can also be applied to many other industries for secure, transparent data management.

Ethereum is a popular, decentralized blockchain platform that enables developers to build and run decentralized applications (dApps). Unlike Bitcoin, which is primarily designed as a digital currency, Ethereum allows developers to create smart contracts—self-executing contracts with the terms of the agreement directly written into code. Ethereum's native cryptocurrency is called Ether (ETH), which is used to pay for transactions and computational services on the network.

• Blockchain is the technology behind secure, decentralized record-keeping.
• Ethereum is a specific blockchain platform that supports the creation of smart contracts and decentralized applications.