Likely you're all being tongue-in-cheek but just in case,
"An environmental portrait is a portrait executed in the subject's usual environment, such as in their home or workplace, and typically illuminates the subject's life and surroundings. By photographing a person in their natural surroundings, it is thought that you will be able to better illuminate their character, and therefore portray the essence of their personality, rather than merely a likeness of their physical features. It is also thought that by photographing a person in their natural surroundings, the subject will be more at ease, and so be more conducive to expressing themselves, as opposed to in a studio, which can be a rather intimidating and artificial experience."
I much prefer an almost "abstract" setting of careful lighting and featureless neutral background for a portrait, but that's just me.