The foyer originally referred to the entrance gate to Buddhism, now it generally refers to the outer door of a hall, or the area at the entrance of a living space. Specifically, it denotes a transitional space between the indoor and outdoor areas of a residential building, where one can change shoes or clothes upon entering, or serve as a buffer space when moving from indoors to outdoors. Some also call it a small room, hallway, or vestibule.

The foyer is the transitional space between the indoors and outdoors, a buffer zone. It allows for a good buffer between the exterior and interior, enhancing the residents' privacy, and also serves as a strong decorative function, with excellent feng shui effects.

Here's the basic information about the foyer; hope it's helpful to you.