Pile, n.
 1. A large stake, or piece of timber, pointed and driven into the earth, as at the bottom of a river, or in a harbor where the ground is soft, for the support of a building, a pier, or other superstructure, or to form a cofferdam, etc.
 Note: ☞ Tubular iron piles are now much used.
 2.  Her. One of the ordinaries or subordinaries having the form of a wedge, usually placed palewise, with the broadest end uppermost.
 Pile bridge, a bridge of which the roadway is supported on piles.
 Pile cap, a beam resting upon and connecting the heads of piles.
 Pile driver, or Pile engine, an apparatus for driving down piles, consisting usually of a high frame, with suitable appliances for raising to a height (by animal or steam power, the explosion of gunpowder, etc.) a heavy mass of iron, which falls upon the pile.
 Pile dwelling. See Lake dwelling, under Lake.
 Pile plank Hydraul. Eng., a thick plank used as a pile in sheet piling. See Sheet piling, under Piling.
 Pneumatic pile. See under Pneumatic.
 Screw pile, one with a screw at the lower end, and sunk by rotation aided by pressure.


 Pneu·mat·ic Pneu·mat·ic·al a.
 1. Consisting of, or resembling, air; having the properties of an elastic fluid; gaseous; opposed to dense or solid.
    The pneumatical substance being, in some bodies, the native spirit of the body.   --Bacon.
 2. Of or pertaining to air, or to elastic fluids or their properties; pertaining to pneumatics; as, pneumatic experiments. “Pneumatical discoveries.”
 3. Moved or worked by pressure or flow of air; as, a pneumatic instrument; a pneumatic engine.
 4. Biol. Fitted to contain air; Having cavities filled with air; as, pneumatic cells; pneumatic bones.
 5. 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 action, or  Pneumatic lever Mus., a contrivance for overcoming the resistance of the keys and other movable parts in an organ, by causing compressed air from the wind chest to move them.
 Pneumatic dispatch, a system of tubes, leading to various points, through which letters, packages, etc., are sent, by the flow and pressure of air.
 Pneumatic elevator, a hoisting machine worked by compressed air.
 Pneumatic pile, a tubular pile or cylinder of large diameter sunk by atmospheric pressure.
 Pneumatic pump, an air-exhausting or forcing pump.
 Pneumatic railway. See Atmospheric railway, under Atmospheric.
 Pneumatic syringe, a stout tube closed at one end, and provided with a piston, for showing that the heat produced by compressing a gas will ignite substances.
 Pneumatic trough, a trough, generally made of wood or sheet metal, having a perforated shelf, and used, when filled with water or mercury, for collecting gases in chemical operations.
 Pneumatic tube. See Pneumatic dispatch, above.

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