Piston

n.

1.

(Mach.) A sliding piece which either is moved by, or moves against, fluid pressure. It usually consists of a short cylinder fitting within a cylindrical vessel along which it moves, back and forth. It is used in steam engines to receive motion from the steam, and in pumps to transmit motion to a fluid; also for other purposes. Piston head (Steam Eng.) that part of a piston which is made fast to the piston rod. Piston rod a rod by which a piston is moved, or by which it communicates motion. Piston valve (Steam Eng.) a slide valve, consisting of a piston, or connected pistons, working in a cylindrical case which is provided with ports that are traversed by the valve.

Noun	1.	Piston - United States neoclassical composer (1894-1976) Synonyms: Walter Piston
	2.	piston - mechanical device that has a plunging or thrusting motion Synonyms: plunger

composer, Walter Piston