A band is a small section of the spectrum of radio communication frequencies, in which channels are usually used or set aside for the same purpose. Examples include:
Note that as a matter of physics, bands are divided at wavelengths of 10nmetres, or frequencies of 3×10nhertz. For example, 30MHz or 10m divides shortwave (lower and longer) from VHF (shorter and higher). These are the parts of the radio spectrum, and not its frequency allocation.