1. of or relating to or using air (or a similar gas)
pneumatic drill|pneumatic tire
2. Consisting of, or resembling, air; having the properties of an elastic fluid; gaseous; opposed to dense or solid.
3. Adapted for containing compressed air; inflated with air; as, a pneumatic cushion; a pneumatic tire, a tire formed of an annular tube of flexible fabric, as India rubber, suitable for being inflated with air.
4. A vehicle, as a bicycle, the wheels of which are fitted with pneumatic tires.