The Collaborative International Dictionary
Piston \Pis"ton\, n. [F. piston; cf. It. pistone piston, also pestone a large pestle; all fr. L. pinsere, pistum, to pound, to stamp. See Pestle, Pistil.] (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.
Usage examples of "piston head".
He listened as the piston head thundered down, then nodded to his secretary skutter to tick the check sheet, and moved on to piston tower 138.
At this open end was the circle of an immense piston head which fitted tightly into the walls of the huge cylinder.
It could be seen this amplified power would drive the piston head slowly, but with irresistible force into the cylinder.
After each tower had been primed, its eight-thousand-ton piston head had to be tested.