piston ring

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.
Also called packing ring, ring.
Origin
1865-70
Examples from the web for piston ring
  • It became one of the largest piston ring manufacturers in the world.
  • Oil consumption and crankcase contamination are reduced by using a newly designed upper piston and piston ring.
  • The failed piston ring seals were fabricated from resin impregnated leather.
  • piston ring wall thickness was increased to displace refrigerant gas in the ring groove of the piston.
  • One of the rope brake components subjected to wear was the piston ring gasket.
  • The engineering crew began replacing a damaged exhaust valve gear piston ring and several o-rings.
British Dictionary definitions for piston ring

piston ring

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