What is Nonce in WordPress?

Nonce are Number only used once which is used when there is a secure operation need to be done. Nonces are valid for short period of time and expire, they can be only used once.
Nonces are used in cases like when we authorize some service with Wordpress, authorize any plugin or activating users etc.

In WordPress, a nonce (short for "number used once") is a security measure that helps protect against certain types of hacking attacks, such as cross-site request forgery (CSRF). A nonce is a unique token that is generated by the WordPress software and included in certain URLs or forms on the website. When a user submits a form or clicks a link that contains a nonce, the token is checked by the WordPress software to ensure that it is valid and has not been used before. This helps prevent unauthorized actions from being performed on the website.