What does the term "ceiling" refer to in aviation?

The term "ceiling" in aviation specifically refers to the lowest broken or overcast layer of clouds above the ground. This definition is crucial for pilots as it indicates the height at which visibility may become restricted due to cloud cover. Understanding the ceiling is vital for safe flight operations, especially in terms of visual flight rules (VFR) and instrument flight rules (IFR).

A broken cloud layer is defined as having 5/8 to 7/8 of the sky covered with clouds, while an overcast layer means the sky is completely covered. Knowing the ceiling helps pilots assess whether they can safely operate visually or if they need to rely on instruments for navigation. The other options, while related to aviation, do not accurately capture the definition of ceiling as it is used in meteorological terms for flight operations.