Other forms: axles
An axle is the rod a wheel turns on, or the bar running across between two wheels. Look under a car and the axle is the shaft joining the front pair; on a skateboard it is the little metal pin the wheel spins around.
Lorries are counted by them, so you get a three-axle truck and an axle-weight limit posted on a bridge, and railway wagons ride on axles that carry both wheels as one rigid pair. Axle grease is thick and black, and an axle that snaps leaves the vehicle exactly where it stands. The word to keep separate is axis: an axle is a physical bar you could hold in your hands, while an axis is an imaginary line, like the one the Earth turns on. Nothing spins around an axle in the abstract sense. The fitting at each end of it is the hub.
1nounaxleA rod or shaft that a wheel turns on, or that joins a pair of wheels and turns with them.
“The back axle broke on the farm track.”
synonyms: shaft, spindle
axle is a rod.
Axle is Old English eaxl, which meant the shoulder or the armpit. It comes from Proto-Germanic *ahslō, 'shoulder', and a Proto-Indo-European root *h₂eḱs- meaning axis or axle, the same root behind Latin axis and axilla, 'armpit'. German still calls the armpit die Achsel, and the link makes sense: the shoulder was the first joint anybody watched an arm turn on.
Proto-Indo-European
*h₂eḱs-
Proto-Indo-European
*h₂eḱs-l-eh₂
Proto-Germanic
*ahslō — shoulder
Proto-West Germanic
*ahslu — shoulder
Old English
eaxl — shoulder, armpit
Middle English
axel
English, today
axle
Built from
From Middle English axel, axle, eaxle, from Old English eaxl (“shoulder, armpit”), from Proto-West Germanic ahslu (“shoulder”), from Proto-Germanic ahslō (“shoulder”), from Proto-Indo-European h₂eḱs-l-eh₂, from h₂eḱs- (“axis, axle”). Cognate with stq acsle (“shoulder”), Dutch oksel (“armpit”), German Achsel (“armpit”), Swedish axel (“shoulder”), Latin axilla (“armpit”), Latin axis (“axle”) (whence English axis, atelier, and via Latin āla English ala, aisle), Ancient Greek ἄξων (whence English axo-, axon), Greek άξονας (“axle”), Sanskrit अक्ष (“axle”), Sanskrit कक्ष (“room, armpit”), Russian ось (“axle”).
Etymology from Wiktionary, CC BY-SA