| piston | <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. Piston head, 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. Origin: F. Piston; cf. It. Pistone piston, also pestone a large pestle; all fr. L. Pinsere, pistum, to pound, to stamp. See Pestle, Pistil. Source: Websters Dictionary (01 Mar 1998) |
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| piston pulse | <radiology> Corrigan's sign: increased pulse at wrist, aortic insufficiency, widened pulse pressure due to increased stroke volume, diastolic regurgitation (12 Dec 1998) |