Persona

A fictional but research-based profile of a type of user, with goals, context, behaviors and frustrations, used to keep design decisions anchored to someone specific

Popularized by Alan Cooper in The Inmates Are Running the Asylum (1999). A persona is only as good as the research behind it: one invented in a workshop describes the team, not the user. Jobs-to-be-done is the common complement, since it focuses on the goal rather than the person.