Layer 2 refers to a secondary framework built on top of a primary blockchain, such as Bitcoin or Ethereum. Its main purpose is to enhance scalability and transaction speed by processing transactions off the main chain while still benefiting from the security of the underlying blockchain. These solutions, like Lightning Network for Bitcoin or Optimistic Rollups for Ethereum, allow for faster and cheaper transactions. By reducing the load on the main blockchain, Layer 2 technologies help improve user experience and make decentralized applications more efficient and accessible.