Microwaves heating is often referred to as dielectric heating, but I'm not sure why this seems so special to specify of all the different thermal radiation frequencies. Doesn't infrared heat the dielectric material as well in a similar process? Isn't radiation heat transfer common for a wide range of EM frequencies (radio to ultraviolet)? I already know the answer to that last question - that heat transfer is not specific to just the infrared or microwave, but then that's why I am confused of our references to thermal radiation as infrared only. So, why is infrared considered "thermal radiation" while others really are not? I know that some frequencies can actually bump electrons to higher energy states, and this might be considered different from dielectric heating as a form of energy transfer, but there are still many frequencies that are absorbed by a material and heated besides just infrared. Does anyone see why I'm confused, or can you clarify this some what?