Definition of oil ring in US English:

oil ring

noun

  • Engineering. A ring or chain which dips into an oil reservoir and continuously lubricates a shaft or bearing around which it revolves. Also: a piston ring serving to prevent leakage of lubricants from the cylinder.

Origin

Mid 19th century; earliest use found in Engineering. From oil + ring.

Pronunciation

oil ring

/ˈɔɪl rɪŋ/