Nonce in blockchain terminology stands for “Number used only once”. It is a four-bit number that gets added to encrypted or hashed data in a blockchain, which, when rehashed, reaches the difficulty restriction levels.

The nonce is the number that the blockchain miners try to identify. Once identified, the miner is rewarded for the same. In order to secure the data of the blockchain, the data from the previous blocks are hashed into a series of numbers, which serves as the block header for the next block. This header contains the version number, timestamp, the difficulty target, hash from the previous block, and the nonce.

The nonce is used by miners to validate the information contained within a particular block. The miner tries to identify the nonce of the block by solving some mathematical calculations. If the value does not match the target, the nonce is increased by one, and the process restarts. The process continues until the miner meets their target.