What defines "Ceiling" in meteorological terms related to aviation?

In meteorological terms related to aviation, "ceiling" is defined as the distance between the ground and the underside of the lowest layer of clouds. This measurement is crucial for pilots and air traffic controllers as it affects visibility and can influence flight operations, particularly approaches, landings, and takeoffs. A lower ceiling indicates that there are low-hanging clouds, which may affect a pilot's ability to see the ground or the runway.

Understanding the ceiling is essential for ensuring safe flying conditions and compliance with aviation regulations, which require a minimum ceiling for certain types of flying operations, such as visual flight rules (VFR). Knowing this information helps pilots make informed decisions about whether to proceed with a flight or alter their plans based on cloud cover and visibility conditions.