In general, "altitude" refers to distance above mean sea level (MSL or AMSL), "height" refers to distance above a particular point (e.g. the airport, runway threshold, or ground at present location), and "elevation" describes a feature of the terrain itself in terms of distance above MSL.[2][3] One mnemonic that can be used is: if it's an altitude you can fly there, if it's an elevation you can walk there, and if it's height that's how far a rock will fall before it hits the ground.