altitude
height in relation to a certain reference point
clearance
usable height below or inside a structure
aircraft altitude
altitude of an aircraft above a given reference point
density altitude
altitude relative to the standard atmosphere conditions
normal height
altitude above quasigeoid or mean sea level
Armstrong limit
the altitude above which water boils at human body temperature, making it absolutely impossible for humans to survive unpressurized; approx. 18–19 km above sea level
height above mean sea level
elevation of a location in reference to a historic mean sea level taken as a vertical datum
education level
Flanders