the complete range of frequencies of electromagnetic waves from the lowest to the highest, including, in order, radio, infrared, visible light, ultraviolet, X-ray, and gamma ray waves
See electromagnetic spectrum in American Heritage Dictionary 4
noun
The entire range of radiation extending in frequency from approximately 1023 hertz to 0 hertz or, in corresponding wavelengths, from 10-13 centimeter to infinity and including, in order of decreasing frequency, cosmic-ray photons, gamma rays, x-rays, ultraviolet radiation, visible light, infrared radiation, microwaves, and radio waves.
(click for a larger image)
electromagnetic spectrum
electromagnetic spectrum frequencies in hertz
A. gamma raysB. x-raysC. ultraviolet raysD. visible lightE. infrared raysF. microwavesG. radio waves