Nonce

A nonce is a value your miner increments over and over while searching for a valid hash. The rest of the block data stays fixed, but changing the nonce produces a completely different hash each time, so the miner is essentially trying numbers until one hash meets the difficulty target. Billions of nonce values may be tried per second across the network. When a miner finally finds a nonce that produces a qualifying hash, that nonce becomes part of the block as proof the work was done. It is a small field with an enormous role: the entire search underlying proof of work is the hunt for the right nonce.