derailleur

noun

de·​rail·​leur di-ˈrā-lər How to pronounce derailleur (audio)
: a mechanism for shifting gears on a bicycle that operates by moving the chain from one set of exposed gears to another

Examples of derailleur 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.
In theory, this means a mountain bike rear derailleur could be paired with a road-style shifter and work without a fuss (the road shifter hasn’t been released yet, so nobody knows). — ArsTechnica, 15 May 2026 Cannondale doesn't use an e-MTB-specific derailleur, which failed under the speed and torque of an electric motor. — Adrienne So, Wired News, 19 Mar. 2026 Paired with a 7-speed Shimano rear derailleur, the drivetrain ensures smooth, reliable shifting across varied terrain and gradients. — New Atlas, 20 May 2026 Adam Grosser My original idea for shifting was to adapt an electronic derailleur from Shimano—the company’s Di2 system. — IEEE Spectrum, 28 Aug. 2020 See All Example Sentences for derailleur

Word History

Etymology

French dérailleur, from dérailler

First Known Use

1930, in the meaning defined above

Time Traveler
The first known use of derailleur was in 1930

Rhymes for derailleur

See All Rhymes for derailleur

Browse Nearby Words

derail
derailleur
derailment
See all Nearby Words

Cite this Entry

“Derailleur.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/derailleur. Accessed 7 Jul. 2026.

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Kids Definition

derailleur

noun
de·​rail·​leur di-ˈrā-lər How to pronounce derailleur (audio)
: a device for shifting gears on a bicycle that operates by moving the chain from one set of exposed gears to another
Etymology

from French dérailleur "gear changing device," from dérailler "to derail"

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