What does proof of work specifically refer to in blockchain?

Proof of work can be simply understood as a certificate used to confirm that a node has performed a certain amount of work. The entire process of monitoring the work is usually extremely inefficient, and verifying the results of the work to prove that the corresponding amount of work has been completed is a very efficient method. Bitcoin uses the PoW mechanism in the process of block generation; obtaining a reasonable random number to solve a mathematical problem requires numerous attempts at calculations. By checking records and verifying the proof of blockchain information, one can determine whether the specified difficulty level of work has been completed. $Merc