Altitude

The height of a level, point, or object measured in feet Above Ground Level (AGL) or from Mean Sea Level (MSL). (See FLIGHT LEVEL.)
  1. MSL Altitude- Altitude expressed in feet measured from mean sea level.
  2. AGL Altitude- Altitude expressed in feet measured above ground level.
  3. Indicated Altitude- The altitude as shown by an altimeter. On a pressure or barometric altimeter it is altitude as shown uncorrected for instrument error and uncompensated for variation from standard atmospheric conditions.

Source: Pilot Contoller Glossary (PCG)

See also:

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