A persona is a fictional, yet realistic, description of a typical or target user of the product. A persona is an archetype instead of an actual living human, but personas should be described as if they were real people.
When based on user research, personas support user-centered design throughout a project’s life cycle by making characteristics of key user segments more salient.
Personas work because designers and developers have the same tendency as all other people to be captivated more by concrete instances than by abstractions and generalizations. We need all product-team members to empathize with users and be willing to go the extra step to develop something that will work for the actual users. But if users are described in statistical terms and as broad profiles, that information will simply not lodge itself as deeply in team members’ brains as a distinct persona will.