Portrait photography is a picture of a single person or group of people. The photo often aims to demonstrate the personality of the subject(s) with effective techniques such as lighting, background and poses. A portrait does not have to just be a photo of someone or some people from the shoulders up. Portraits can be full body as they are trying to say something about the subject which may not be specific to their face.
Some examples of professional portrait work from Arnold Newman
My examples of Candid and Environmental portrait work:
