[ jak-shaft, -shahft ]
/ ˈdʒækˌʃæft, -ˌʃɑft /

noun Machinery.

Also called countershaft. a short shaft, connected by belting, gears, etc., that transmits motion from a motor or engine to a machine or machines being driven (distinguished from main shaft).
a shaft on which an idle wheel or fairlead turns.

Origin of jackshaft

First recorded in 1895–1900; jack1 + shaft
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

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British Dictionary definitions for jackshaft

/ (ˈdʒækˌʃɑːft) /


a short length of shafting that transmits power from an engine or motor to a machine
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012