axle

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”).