: a ring (as of synthetic rubber) used as a gasket

Examples of O-ring in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Extreme cold made the O-rings fail, but NASA’s culture was just as blameworthy and needed a retrofit more urgently than any piece of shuttle hardware. Meghan Bartels, Scientific American, 28 Jan. 2026 In January 1986, cold temperatures compromised rubber O-ring seals on the solid rocket boosters of the space shuttle Challenger, which led to a tragic accident that claimed the lives of seven astronauts during the launch of the STS-51L mission. Josh Dinner, Space.com, 27 Jan. 2026 In terms of espresso machine repair and maintenance, the Barista Tool's reamer/punch/sewing awl can leverage off the group head gasket, while the combination pliers can help in removing and handling other gaskets and O-rings. New Atlas, 16 Nov. 2025 Overwhelmed by the realization that NASA had not revealed the O-ring issue to astronauts, chief astronaut John Young sent a memo to the entire astronaut corps expressing his outrage. Alice George, Smithsonian Magazine, 18 July 2025 See All Example Sentences for O-ring

Word History

First Known Use

1946, in the meaning defined above

Time Traveler
The first known use of O-ring was in 1946

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Cite this Entry

“O-ring.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/O-ring. Accessed 2 Feb. 2026.

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