What does "proof of work" mean?

"Proof of work" refers to a consensus mechanism used in blockchain networks to validate transactions and secure the network. In essence, it requires participants, often called miners, to solve complex mathematical problems to add new blocks to the blockchain. This process helps to ensure that the transactions are legitimate and prevents double-spending, as it would require an attacker to control a majority of the network's computing power in order to falsify entries.

The system incentivizes miners through rewards, usually in the form of newly created cryptocurrency coins as well as transaction fees. By requiring effort in solving problems, it makes malicious attempts at altering the network extremely computationally expensive and unfeasible.

While proof of work does play a role in the issuance of new coins, it's not primarily defined by that characteristic. Its main function is establishing a consensus among network participants on the state of the blockchain and is fundamental to the operation of cryptocurrencies like Bitcoin.