1. The ordered sequence of all known forms of electromagnetic radiations, extending from the shortest cosmic rays through gamma rays, X-rays, ultraviolet radiation, visible radiation, and infrared radiation, and including microwaves and all other wavelengths of radio energy.
2. The entire range of different types of electromagnetic waves, extending from the very long, low-frequency radio waves, through infrared and light waves, to the very short, high-frequency cosmic rays and X-rays which can be generated physically.

This range of electromagnetic wavelengths extends almost from zero to infinity and includes the visible portion of the spectrum known as light.

3. A list, chart, graph, or diagram showing the relationships among all known types or range of electromagnetic radiation including the range of frequencies and wavelengths.
4. The total range of wavelengths, extending from the shortest to the longest wavelength or conversely, that can be generated physically.

This range of electromagnetic wavelengths extends practically from zero to infinity and includes the visible portion of the spectrum known as light.