derailleur

The story

1. Proto-Indo-European · derived from*h₃reǵ-“to righten; to straighten”
2. French · borrowed fromdérailleur
3. English todayderailleur

Unadapted borrowing from French dérailleur, from dérailler (“to derail”) + -eur (suffix forming masculine agent nouns from verbs). Dérailler is derived from dé- (prefix meaning ‘away; from; off’) + rail (“rail”) (ultimately from Proto-Indo-European *h₃reǵ- (“to righten; to straighten”)) + -er (suffix forming infinitives of first-conjugation verbs). Doublet of derailer.

Words from the same roots

First known use, by meaning

• from early 20th c. A mechanism on a bicycle wheel used while cycling to move the bicycle chain from one sprocket (gear) to another, to change speeds.