validation

noun4

1. •
   The act of validating something.

   • In reality, brains go overboard with this sort of fear validation. They love any chance to prove a fear is valid while ignoring all the reasons it's not. — 2021
2. •
   The process whereby others confirm the validity of one's emotions or perspective.
3. •
   Something, such as a certificate, that validates something; attestation, authentication, confirmation, proof or verification.
4. •
   (US) The process of identifying a new prisoner's gang affiliation.