Proof of Work (PoW) is a consensus mechanism used in blockchain systems to verify transactions and mine new blocks.

Basically, Proof of Work is a system with the main purpose of preventing cyberattacks, such as Distributed Denial of Service (DDoS). By sending fake requests, the power of computer system resources can be depleted by such attacks.

Therefore, it can be concluded that Proof of Work is a system that prevents malicious use of computing power, such as sending spam emails and launching denial of service.