What does PoW (Proof of Work) mean?

A consensus mechanism where the right to add a block is won by spending real computation — brute-forcing a hash puzzle — so influence costs electricity rather than identities.

It provides Sybil resistance: creating many fake nodes buys nothing unless you also bring proportional hardware. Battle-tested but energy-hungry, which is why many chains moved to Proof of Stake.

Go deeper:

• Proof of work — Wikipedia — diagrams the challenge-response and solution-verification puzzle protocols.