Plain English Meaning
The wheels of the airplane have rubber tires filled with pressurized air. The air inside acts like a cushion that softens the bumps and shocks when the airplane rolls along the ground or touches down.
Full Definition
Air-filled rubber tires fitted to an aircraft's landing gear. They are inflated to a specified pressure so that the compressed air inside, together with the flexible tire structure, absorbs and cushions impact loads during taxi, takeoff, and landing.
Context Anchor
Seen when discussing landing gear, preflight tire checks, and inspections after a hard landing.
Derivation
From the Greek 'pneuma,' meaning 'breath' or 'air.' A device is one that works using . Knowing this makes it that a pneumatic tire is simply a tire that does its job by pressurized air.