A node is a computer or software process that participates in a blockchain or distributed ledger network by performing one or more functions such as receiving, verifying, storing, or relaying transactions and ledger data.
Nodes can have different roles. A full node verifies protocol rules and maintains enough ledger state or history to independently validate the chain under the network's design. Lightweight clients can verify a smaller set of information. Validator nodes or mining nodes can also participate in consensus and block production. The term node therefore does not imply that every participant stores a complete copy of all historical data.
A node is a network participant. A validator is a node or participant with a specific consensus role under a protocol such as proof of stake.
Nodes distribute transaction data and enforce network rules, making them part of the infrastructure through which stablecoin transactions propagate and are verified.
A full node can verify a stablecoin transaction against the blockchain's protocol rules and relay the transaction to peers.