derailleur

noun

de·​rail·​leur di-ˈrā-lər 

: 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

Paddy: don't know how this cassette works, or this derailleur works, Scott: What is rebound exactly? —Outside Online, 19 Mar. 2025

That's probably a good thing, as the distance between the cranks and rear derailleur requires three traditional bike chains linked together. —John Timmer, Ars Technica, 12 May 2024

Park Tool guide to bicycle brakes 6: Shift the derailleurs With the rear wheel off the ground, spin the pedals and shift through the gears. —George Petras, USA Today, 2 Apr. 2025

This bike has an alloy crank for steady gearing and twist shifters with a rear derailleur. —Bestreviews, The Mercury News, 26 Mar. 2025

Word History

Etymology

French dérailleur, from dérailler

First Known Use

1930, in the meaning defined above

Rhymes for derailleur

• blackmailer
• inhaler
• retailer
• wholesaler
• bailer
• bailor
• baler
• jailer
• jailor
• paler
• sailer
• sailor

Kids Definition

derailleur

noun

de·​rail·​leur di-ˈrā-lər 

: 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"