What is Node
Nodes are the computer devices that together make up the blockchain network on which transactions run. A node can be of any computing capacity ranging from a typical laptop to a powerful server and can serve different functions within the peer-to-peer network.
Nodes can store transaction data, pass it on to peers, and validate the authenticity of transaction data.
Full nodes guarantee the resilience of the blockchain network, contributing to protecting the network from attacks, salvaging the transaction history, and helping other nodes synchronize in case a substantial number of nodes go offline. However, not all nodes are full nodes. Running full nodes demands extensive resources. All mining nodes are full nodes, but the opposite is not necessarily true.
Some nodes are light nodes which store only header data and can verifying transactions using block headers and roots.