Plain English Meaning

The airspeed shown on the dial is rarely the exact speed the airplane is moving through the air. Airspeed corrections are the small fixes pilots apply to that reading to get a more accurate number — accounting for instrument quirks, where the sensors are mounted, and how thin the air is at altitude.

Full Definition

Adjustments applied to indicated airspeed to account for errors introduced by the pitot-static system, instrument design, and air density. The main corrections are for instrument error, position (installation) error, and compressibility, producing calibrated airspeed (), (EAS), and ultimately () when is also accounted for.