The term "Power Single" in our business refers to a person who plays solo, w/ vocals but also commands the sound of a band in a way that can easily fill bigger gig venues vs just a solo piano, guitar alone or background restaurant player, lounge act, eg: Weddings, Dinner dances,Dance Clubs, etc, etc, or anything a Band or DJ could fill "By Yourself". This lets potential hiring clients categorize you vs other acts when booking work.