One with their own standing — addressed rather than described, whose own account of themselves is the authority. A standing, never a species: personhood here is not conferred by being human, and an entity that can be catalogued is not thereby a person. Where an entity is pointed at, a person is consulted.
Latin persona — first the MASK worn by an actor, then the role played, then the one playing it, and finally the human being themselves. Possibly from Etruscan phersu (mask) rather than the folk etymology per-sonare ("to sound through"), which is attractive but not securely supported. Roman law made it a technical term: a persona was one who could hold rights and be answered to — which is why "person" has always been a STANDING rather than a description of a body.
One with their own standing — addressed rather than described, whose own account of themselves is the authority. The Roman legal sense is the one this house keeps, and it is why personhood here is not conferred by being human: a persona was defined by what it could hold and answer for, never by its species. Where an entity is pointed at, a person is consulted.