Piston
Piston , noun
[French piston; compare Italian pistone piston, also pestone a large pestle; all from Latin pinsere, pistum, to pound, to stamp. See Pestle, Pistil.]
(Machinery) 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.
Collocations (3)
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.