axle
n.the central bar or rod that connects a pair of wheels. It allows the wheels to turn so a vehicle can move.
n.a central shaft for a rotating wheel or gear. On a vehicle, it may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around it.
“The car cannot move because the front axle is broken.”
“The heavy truck was forced to stop after the rear axle snapped under the weight of the cargo.”
“Engineers must calculate the maximum load each axle can support to prevent structural failure during high-speed transit across uneven terrain.”
Often used in technical or mechanical contexts; frequently paired with 'front' or 'rear' to specify location on a vehicle.
“In Amiens, he skidded into a telegraph pole and destroyed the axle, but he was back behind the wheel before long.”
“It’s not just a broken wagon axle that can send a trip sideways.”
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 Saterland Frisian 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 (áxōn) (whence English axo-, axon), Greek άξονας (áxonas, “axle”), Sanskrit अक्ष (ákṣa, “axle”), Sanskrit कक्ष (kakṣá, “room, armpit”), Russian ось (osʹ, “axle”).
From Middle English axil, in turn a combination of Old English eax and Old Norse ǫxull.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.