A light node, also known as a light client, is a software application that allows users to interact with a blockchain network without needing to download and synchronize the entire blockchain. Instead, it connects to full nodes, which maintain a complete copy of the blockchain, to request and verify specific information using cryptographic proofs, like Merkle tree roots. Light clients significantly reduce storage and resource requirements, enabling them to operate on devices with limited capabilities, such as mobile phones. While they offer a more user-friendly experience, light clients do not contribute as much to the network's overall security and robustness, as they only verify and relay the information necessary for their purposes.