The Electromagnetic (EM) wave is a carrier medium. It provides us with long range communication and is the base transporting layer of so called modern communication. But it is also masqueraded: although we use it all the time, we access it using tools provided to us by the cooperation of our choice, which brings up another point of EM waves. I would describe it as a territory. Frequency ranges are licensed to "providers" and national borders are marked by messages informing us of the transition to one of their "roaming" partners.