Altimeter
measures height above a certain air pressure level (gives pilot altitude)
indicated altitude
uncorrected altitude read right from altimeter
true altitude
vertical distance of airplane above sea level
absolute altitude
vertical distance of airplane above terrain/ground level
pressure altitude
altitude indicated when altimeter is set to standard conditions
density altitude
the pressure altitude corrected for conditions that aren’t standard
standard barometric measurements
29.92 inches of mercury, 15 C or 59 F