Pressure altitude corrected for temperature. It is a measure of air density.
Pressure altitude (as shown on an altimeter) referenced to temperature for computing aircraft performance.
The altitude at which a given density is found in the standard atmosphere. Used in aviation, it is computed from the station pressure at takeoff and the virtual temperature at the particular altitude under consideration.
Density altitude is the altitude in the International Standard Atmosphere at which the air density would be equal to the actual air density at the place of observation. "Density Altitude" is the pressure altitude adjusted for non-standard temperature.