Glossary » persona
a description of a specific person who is a target user of a system being designed, providing demographic information, needs, preferences, biographical information, and a photo or illustration. Typically, multiple personas are developed in the early stages of design that represent the spectrum of the target audience. Personas are one piece of a “scenario”, the other piece being a description of how this person would typically interact with the system being designed.
The point of developing personas is to avoid the trap of designing for the “average” user that doesn’t actually exist, and instead to make sure that the system will work for somebody specific rather than no one in particular.