The quantity – pV2 is usually referred to as the dynamic pressure. There is a more precise definition of dynamic pressure, but this need not concern us now. Although it has the same units as pressure, dynamic pressure actually represents the kinetic energy of a unit volume (e. g. 1 cubic metre) of air.
Aerodynamic forces such as lift and drag are directly dependent on the dynamic pressure. It is, therefore, a factor that crops up frequently, and for simplicity, it is often denoted by the letter q. Pilots sometimes talk of flying at ‘high q’, meaning high dynamic pressure.
The other term in the expression, the pressure p, is often referred to as the static pressure.