Re: why is indigo not in the rainbow any more?

I am concerned about the removal of indigo from the rainbow line-up. Now the Roy G. Biv has a consonant only last name, Bv. English teachers should have a field day with that one. What is next, removal of Re, from Doe, Re, Me?!

That aside, the color labels mean nothing, just like the Doe Re Me's are labels for particular notes, the color labels are for a particular frequency. There are actually a continuum of colors (some for which crayons have not been invented yet), just as there are a continuum of frequencies of sound. What exactly is yellow anyway? Sometimes in science it means the defining of a single frequency or wavelength, say 500 nanometers. However, those wavelengths of electromagnetic radiation which our eyes perceive as "yellow" extend across a whole range of wavelengths.