Our world(s) are full of color, but do all cultures see the same thing? While the scientific basis of color perception is the same for all people, the wavelengths of light do not determine how we name color impressions, into how many (and what kind of) categories we divide them, and what meanings and associations we ascribe to these colors.
This can all be very different depending on the language and culture. Color is therefore not necessarily the same as color. For example, the meaning of the Japanese word ao is not identical with the German color word blue. Just as little as midori is synonymous with green. Thus, Japanese poetry may well speak of "green sky" and "blue grass" - our European visual habits are turned upside down.