What is the aviation definition of height?

The aviation definition of height is specifically identified as the distance above the ground. This term is often used in aviation when discussing the altitude of an aircraft in relation to the terrain below. It is important because it provides pilots with essential information about their aircraft's position relative to the immediate surface, which is crucial for safe navigation, takeoff, and landing procedures.

In aviation contexts, height helps determine if the aircraft is flying at a safe elevation above obstacles such as buildings, mountains, or other terrain features. This distinguishes it from altitude, which typically refers to the distance above a predetermined reference point, commonly sea level.

Other options provided in the question do not align with aviation terminology in the same way. For instance, distance above sea level refers to altitude rather than height, distance from the horizontal plane is not a standard measurement used in aviation, and distance from the nearest airport is contextually irrelevant to defining height as it does not focus on an aircraft’s position in relation to the ground directly beneath it.