What is the definition of absolute altitude?

The definition of absolute altitude refers to the actual height of an object above a specified reference point, which in aviation typically means the height above the ground level directly below the aircraft. Thus, the correct choice indicates that absolute altitude is indeed concerned with the distance from an aircraft to the ground level, which can vary depending on terrain features.

In contrast, other definitions provided focus on different reference points. The actual altitude above Mean Sea Level concerns a global average reference point, while uncorrected altitude displayed on the dial refers to a raw reading that may not factor in atmospheric conditions. Lastly, pressure altitude adjusted for density relates to another measurement used primarily for performance calculations rather than a direct measure of distance above the ground.