What is it called when one spur is used to turn several other spur gears?

When one spur gear is used to turn several other spur gears, it is referred to as a "gear train." In a gear train, the driving gear (the one with the spur) transfers motion and torque to the driven gears, allowing for the transmission of power through multiple gears. This arrangement is commonly used to achieve different speed and torque outputs in machinery.