- Consisting of, or resembling, air; having the
properties of an elastic fluid; gaseous; opposed to dense or solid. - Of or pertaining to air, or to elastic fluids or their
properties; pertaining to pneumatics; as, pneumatic experiments. - Moved or worked by pressure or flow of air; as, a
pneumatic instrument; a pneumatic engine. - Fitted to contain air; Having cavities filled with
air; as, pneumatic cells; pneumatic bones.