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

These particles can indicate piston ring wear, bearing wear, distributor and oil pump wear.

From Time Magazine Archive

The others examined it and Paul remarked: “Guess it’s a case of broken piston ring, eh, Jack?”

From The Motor Girls in the Mountains or, The Gypsy Girl's Secret by Penrose, Margaret