1. A shaft in machinery that is driven by and transmits motion to another shaft, typically used to change speed or direction of rotation.
Usage: technical; plural form of countershaft

Examples

• The countershafts in the transmission system help regulate the speed of the machinery.
• Engineers designed multiple countershafts to distribute power efficiently throughout the engine.
• The factory's old mill relied on countershafts to transfer motion from the main drive shaft to individual workstations.
• Modern automotive transmissions use countershafts to enable different gear ratios.
• The countershafts were carefully aligned to minimize vibration and wear.