Definitions

1. noun

A device or system, especially one on a ship, that controls or operates something, such as a winch or a windlass, especially one with a rotating drum.

“The crew used the jackbox to lift the heavy load into place.”

2. noun

A mechanical device, especially one on a printing press, that performs a particular operation, such as cutting or folding, at a specific stage in the printing process.

“The jackbox malfunctioned, causing the printer to jam.”