There are various terms that are used to describe mercury-vapor lamps. One of the most common is MV lamps, which stands for mercury-vapor lamps. Another term that is frequently used is HQL lamps, which stands for high-pressure mercury-vapor lamps. These lamps are also sometimes referred to as mercury vapor discharge lamps. They have been used for decades in a range of applications, including street lighting, industrial lighting, and outdoor lighting. Despite being less efficient than some newer technologies, mercury-vapor lamps continue to be used because of their long lifespan and low operating costs. Other terms that can be used to describe these lamps include high-intensity discharge lamps and HID lamps.