A node is any device that participates in a blockchain network. Nodes maintain the blockchain's functionality and uphold its decentralized nature. They can be personal computers, servers, or even dedicated devices.
"Your laptop can act as a node if it runs software like Bitcoin Core, connecting it directly to the Bitcoin network."
A full node is a node that holds a complete copy of the blockchain and validates all transactions and blocks against the network's consensus rules. Full nodes contribute to the security and robustness of the network.
"Running a full node allows you to independently verify transactions without needing to trust any third party."
A mining node, which is always a full node, additionally participates in the creation of new blocks. When a mining node solves a cryptographic puzzle (proof-of-work), it broadcasts the solution (the new block) to the network.
"Mining nodes compete to solve complex mathematical problems. The first to solve it gets to add a new block to the blockchain and is rewarded with some cryptocurrency."
A light node, or lightweight node, does not hold a complete copy of the blockchain. Instead, it downloads only the necessary data, making it suitable for devices with limited resources. However, light nodes rely more on other nodes for information.
"Mobile wallet apps often run as light nodes, as they don't require the device to store the entire blockchain."
* All terms and definitions may update as the Cryptionary improves.