This is a widely used term which is technically not correct. The correct terms are UL Listed or UL Recognized.

UL grants this form of approval to equipment that will be user installed or operated and that is found to meet the safety requirements of the applicable UL standards. If a product is UL Listed, then it must be marked with the UL insignia.

Equipment that utilizes electric energy for electronic, electromechanical, chemical, heating, lighting, or similar purposes.