1. of air pressure; inflated, full of air; pertaining to air, of air. pneumaticpneu*matic , n. a vehicle, as a bicycle, the wheels of which are fitted with pneumatic tires. [pneumatic pneu*matic, pneumatical pneu*matic*al ], a. 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.pneumatic pneu*matic , pneumatical pneu*matic*al , ] a. [l. pneumaticus, gr. , fr. , , wind, air, to blow, breathe; cf. ohg. fnehan: cf. f. pneumatique. cf. pneumonia.]