derailleur

American  

[dih-rey-ler] / dɪˈreɪ lər /

noun

1. a gear-shifting mechanism on a bicycle that shifts the drive chain from one sprocket wheel to another.

---

derailleur British  

/ dəˈreɪljə /

noun

1. a mechanism for changing gear on bicycles, consisting of a device that lifts the driving chain from one sprocket wheel to another of different size

---

Etymology

Origin of derailleur

1945–50; < French dérailleur literally, a device causing disengagement or derailing, equivalent to déraill ( er ) to derail + -eur -eur

Example Sentences

A single derailleur cable found snapped in two during a bike ride I took in Italy morphed into something more sinister.

From Washington Post

The ’70s also saw an explosion in bike sales, both as a result of high gas prices and the introduction of the 10-speed derailleur.

From The Verge

Using the updated Google Lens to identify a bike’s derailleur.

From The Verge

These designs often require absurdly long chains slung between the pedals and rear derailleur.

From The Verge

The recumbent trikes have been waiting for months for rear derailleurs, a small but crucial part that is built in Taiwan.

From New York Times