Definitions for "Indicated airspeed"
The speed shown by the aircraft's airspeed indicator measuring the pressure of the air striking the front of the aircraft as it moves forward. It is affected by atmospheric pressure, being close to the true airspeed at low altitudes and differing more as altitude increases.
The speed of an aircl shown on its pitot static airspeed indicatc brated to reflect standard atmosphere ad compressible flow at sea level uncorrect airspeed system errors.
The speed of an aircraft as shown on its pitot static airspeed indicator calibrated to reflect standard atmosphere adiabatic compressible flow at sea level uncorrected for airspeed system errors.