A portrait is a photograph, painting, sculpture, or other artistic representation of a person that usually only includes the person's head and shoulders. The face and its expression is predominant in portrait.
Most of the portraits are done with the intention to just to show the likeness but also reflect personality and mood of a model. That is why, in photography a portrait is usually not a snapshot, but a composed image of a person in an immovable position. A person posing for the portrait is often looking directly at the painter or photographer, to produce the illusion of an eye contact with the viewer.