Layer 2 refers to a secondary framework built on top of a main blockchain network that allows for increased scalability and transaction speed. This is achieved by moving a significant amount of the processing work off the main chain and onto the second layer, allowing for faster and more efficient processing of transactions. Layer 2 solutions are becoming increasingly popular as they offer a way to address the scalability issues of traditional blockchain networks, such as those seen with Ethereum. Examples of Layer 2 solutions include state channels, plasma chains, and sidechains.