LASER: Light Amplification by Stimulated Emission of Radiation
This is an extremely good question. Unfortunately, the word laser is not a protected word. It has a connotation of advanced technology that can be used to embellish services that are being offered to the consumer. Laser is an acronym (see above) that indicates the electromagnetic process in physics that delivers the energy of treatment.
Lasers are of a single wavelength on the electromagnetic spectrum. They are not "jack of all trades," but are highly sophisticated machines that when used correctly act with precision in treating a specific condition.
IPL stands for Intense Pulsed Light. Quite simply, this is a glorified flashbulb. While it is still very useful when appropriately applied, it is not a laser. Because it is still a light-based energy device, they are often incorrectly described as lasers. This is simply a marketing technique used by some, and misleads the public. An intense puled light machine is less sophisticated than a laser in most cases, and therefore cheaper to purchase and more readily available to non-physicians.
The service that is the most corrupt by the improper naming of an IPL device is "Laser Hair Removal." Both an IPL and a true laser are offered in the hair removal service industry. If your experience during a hair removal treatment feels like an intense snapping of a rubber band on your skin, this is not a laser; it is an IPL device. In my opinion, an IPL is not the best device for hair removal. Not only are they unnecessarily uncomfortable compared to a laser, but they are not specific to hair, whereas a laser is.
Intense pulsed light (IPL), has its place, but most be appropriately disclosed for what it is to the public, and appropriately sold for the proper job.