true name

noun2

1. •
   The unique name of an entity, which can be used to control or manipulate that entity.

   • It would be back to the stone floors and getting up when it was still dark and no alcohol under any circumstances and memorising the true names of everything until the brain squeaked. — 1987
2. •
   A person's preferred name, particularly where this does not match their legal name.

   • I suggested to Sofie that another baptism wasn't necessary since God always knew her deepest self, but we could do an affirmation of baptism with her true name. — 2020