"Off-Chain" refers to transactions or data that occur outside of a blockchain network. This means that the information is not recorded directly on the blockchain, which can help reduce congestion and improve speed. Off-chain solutions are often used to handle large volumes of transactions without burdening the blockchain itself. Common examples of off-chain methods include payment channels and sidechains. These techniques allow users to conduct transactions privately and quickly, later settling the final results on the main blockchain. This approach can enhance scalability and efficiency while still benefiting from the security of the underlying blockchain technology.