Front of House (FOH) is where lighting audio and some video personnel are placed. Usually, FOH is placed at the back of your auditorium or right under the front edge of your balcony. It’s common that FOH is the best place to hear audio.
Front of House is also used in the restaurant industry to refer to the public parts of bars and restaurants that guests interact with. Think the dining room, bar, cocktail area, patio, private dining rooms, waiting area, and coat check.