The mechanical frame and cable system that physically lifts the window.
Press the switch. If you hear a motor whirring or a grinding sound but the glass doesn’t move, your motor is likely fine, but the regulator has failed (often snapped cables). No sound usually points to an electrical issue like a blown fuse or dead switch.
If you press the switch and hear the motor whirring or a clunking sound, but the glass remains stationary, the electrical system is working, but the mechanical linkage is broken.