Plain English Meaning

It's simply the speed shown on the airspeed dial in front of you. The number hasn't been adjusted for any errors or for the thinner air at altitude — it's the raw reading.

Full Definition

The airspeed read directly from the airspeed indicator in the cockpit, uncorrected for installation error, instrument error, or variations in air density due to altitude, temperature, or compressibility. It is derived from the difference between ram (pitot) air pressure and static air pressure, displayed as a speed value.