Term - Idler Gear
From VEX Wiki
Gears can be inserted between the driving and driven gears. These are called idler gears, and they have no effect on the robot's gear ratio because their gear ratio contributions always cancel themselves out (because they are a driven gear relative to the first gear, and a driving gear relative to the last gear—you first multiply by the number of teeth on the idler gear and then divide by the same number, which always cancels out).
However, idler gears do reverse the direction of rotation. Normally, the driving gear and the driven gear turn in opposite directions. Adding an idler gear makes them turn in the same direction. Adding a second idler gear makes them turn in opposite directions again. Idler gears are typically used either to reverse the direction of spin between two gears or to transmit force from one gear to another gear far away (by using multiple idler gears to physically bridge the gap).
