piston ring

American  

noun

1. a metallic ring, usually one of a series, and split so as to be expansible, placed around a piston in order to maintain a tight fit, as inside the cylinder of an engine.

---

piston ring British  

noun

1. a split ring, usually made of cast iron, that fits into a groove on the rim of a piston to provide a spring-loaded seal against the cylinder wall

---

Etymology

Origin of piston ring

First recorded in 1865–70

Example Sentences

He rested his hand on a rack of piston ring installers and timing gear pullers, and this man who lost so much of his family to hurricanes started talking about the parts of them.

From The Guardian • Sep. 13, 2018

When he finally completed his design and took the finished piston ring to Toyota, he was told that the work was not up to their standards.

From Forbes • Mar. 21, 2014

While still at engineering school, he started a workshop with the intention of developing a piston ring for sale to Toyota.

From Forbes • Mar. 21, 2014

And General Motors ran an isotope-treated piston ring in an engine for two hours, later probed the engine's oil to see how much of the ring had worn off.

From Time Magazine Archive

It is advisable to fit each piston ring individually and to mark them in some way to insure that they will be placed in the groove to which they are fitted.

From Aviation Engines Design?Construction?Operation and Repair by Pag?, Victor Wilfred