Definition
The airspeed shown directly on the airspeed indicator in the cockpit, uncorrected for installation error, instrument error, or variations in air density due to altitude and temperature. It reflects the dynamic pressure sensed by the pitot-static system at the moment of reading.
Plain English
It is simply the speed number you see on the airspeed dial in front of you, exactly as the instrument displays it, with no corrections applied.
Context Anchor
You use IAS constantly in normal flying, especially for takeoff, climb, approach, landing, and staying within published speed limits.
Derivation
‘Indicated’ comes from the Latin indicare, meaning ‘to point out’ or ‘to show.’ In this term it means ‘what the instrument is showing you,’ as opposed to a corrected or calculated value.
Why Pilots Care
Most aircraft operating speeds and stall margins are expressed in IAS because the wing responds to dynamic pressure, not true speed through the air.
Analogy
IAS is like the speed shown on a car’s speedometer: it is the number displayed to you while operating the vehicle, even if a more exact corrected value could be calculated later.
Intuition Check
Indicated does not mean perfectly accurate. It means shown on the airspeed indicator before certain corrections are applied.
Example Sentence 1
On final approach, the pilot held an indicated airspeed of 65 knots until crossing the threshold.
Example Sentence 2
In the traffic pattern the student held 80 knots IAS on downwind to maintain proper spacing.