Blockchain is a distributed ledger technology that allows multiple participants to work together to maintain an ever-growing list of data records, known as blocks. Each block contains a set of transaction records that are linked together and arranged in chronological order. The core features of blockchain include:

1. Decentralization: Blockchains do not rely on a central authority or a single governing entity to maintain the ledger, but are jointly maintained by multiple nodes in the network.

2. Immutability: Once a transaction is recorded on the blockchain, it is nearly impossible to change or delete. Each block contains the hash of the previous block, forming a chain relationship, and any change to the previous block will cause the hash of all subsequent blocks to change, which requires the consensus of the majority of nodes in the network to achieve.

3. Transparency: All transactions on the blockchain are visible to all participants in the network, ensuring a high level of transparency.

4. Security: Blockchains typically use advanced cryptography to protect the integrity and security of data. Each block is secured by complex mathematical puzzles that require a lot of computing power to solve.

5. Automation and Smart Contracts: Blockchains can be programmed to implement self-executing smart contracts that automatically trigger transactions or actions when preset conditions are met, without the involvement of intermediaries.

6. Traceability: Every transaction on the blockchain is recorded and can be traced back to its origin, which helps prevent fraud and increase transparency.

Blockchain technology was originally designed for the Bitcoin cryptocurrency, but has now expanded to many other applications, including supply chain management, financial services, healthcare, voting systems, intellectual property protection, and more. These characteristics of blockchain make it a technology that has the potential to transform multiple industries.