What Is the PoW Mechanism Called “Hashing”?

Hashing in Proof-of-Work (PoW) is the process of using a cryptographic hash function to convert input data (the block header) into a fixed-size string of characters, the hash. Miners repeatedly change a variable in the block header (the nonce) and re-hash the data until they find a hash that meets a specific target difficulty (i.e. starts with a certain number of zeros).

This trial-and-error process is the "work" that secures the chain.