Comment by YZF

Technically the motor is also called "brushless servo motor". AI says: "A servo is a control system that converts a small mechanical motion into a larger one. It can also be used as a noun to describe a part of a machine that controls a larger machine." which sounds reasonable.

Stepper motors can be controlled with closed loop controllers and an encoder. As I said in some other comment way down the only difference between a stepper motor and a brushless servo is that steppers have more poles. A by the way is you can also "step" a BLDC (i.e. run it in open loop just like a stepper motor).