You know how some people can tell you the exact shade of two colors that you consider identical? Turns out that giving colors distinct names in our mind makes us way better at seeing the difference and that is how we chop up the color spectrum from an infinite number of colors to seven. You think blue is completely different because you went to school and being able to tell the difference between blue and green was a requirement for you. If the school told you that the sky is a light shade of green and the forest is a dark shade of green you would adjust your brain accordingly.
I guess my point is that all colors are made up by the state and we indoctrinate our children into the government sanctioned system at an early age.