In a gear system, which gear is typically referred to as the driving gear?

The term "driving gear" refers to the gear that initiates motion in a gear system. This gear exerts force onto another gear, causing it to spin. The driving gear often is the one connected to a power source, such as an engine or motor, and its rotation directly correlates to the movement of other gears in the system.

In contrast, other options like the gear that does not move, the gear providing output, or the largest gear in the system do not define a driving gear accurately. The non-moving gear would be idle, the output gear simply transmits motion rather than initiates it, and the size of the gear doesn't specifically determine if it is the driving gear. Thus, the correct answer highlights the defining characteristics of the driving gear and its primary role in the mechanism.