A full node is a computer that downloads every block and checks every rule for itself: signatures, amounts, the supply schedule, all of it. It accepts nothing because someone said so. If a block breaks a rule, the node rejects it, whoever mined it.
Thousands of independent nodes are what actually enforce Bitcoin's rules. Miners propose blocks; nodes decide whether they are valid. You do not need a node to use bitcoin, and most people rely on someone else's. But running one means your wallet checks payments against rules you verified yourself - the purest version of "don't trust, verify".
💬 Have you ever thought about running your own node?
Binance Academy covers this in more depth: https://www.binance.com/en/academy/glossary/full-node
Next lesson: The EVM: one computer shared by thousands
Trading crypto from Dubai since 2019.