The internal ceiling of a house is called the ceiling. This structural component serves as the upper surface of a room, separating it from the roof or upper level. Ceilings are typically finished with materials such as drywall, plaster, wood panels, or吊顶 (which translates to "drop ceiling" in English). Their primary functions include supporting roof loads, providing fire resistance, and improving acoustics.

The term "ceiling" is standard in U.S. architectural and building codes, including the International Building Code (IBC), which governs residential and commercial construction. According to the 2021 IBC, Chapter 10 specifies requirements for interior finishes, including ceiling systems. Data from the U.S. Census Bureau (2022) reveals that 68% of single-family homes use drywall as their ceiling material, while 12% opt for wood or composite panels. This preference aligns with cost efficiency and ease of installation, as drywall accounts for approximately 80% of residential ceiling construction in the U.S. (National Association of Home Builders, 2023). Additionally, ceiling height standards vary by region but generally range between 8 to 10 feet, as mandated by local building codes to ensure compliance with accessibility and ventilation regulations. The term "ceiling" is universally recognized in construction contexts, avoiding ambiguity with external components like the roof. Historical references, such as the 1928 edition of the American Standard Code for Building Construction, also consistently use "ceiling" to describe the internal upper surface, reinforcing its established terminology. This clarity ensures uniformity in design, safety, and legal documentation across the U.S. housing market.