Opening lines of Wikipedia articles on various colours:
Red is the color at the end of the visible spectrum next to orange and at the opposite end from violet. The wavelength of red light is approximately 620–740 nm on the electromagnetic spectrum. Red is the color of blood ...
Yellow /[phonetic]/ is the color of gold, butter, and ripe lemons. In the spectrum of visible light, and in the traditional color wheel used by painters, yellow is found between green and orange. It is a primary color in subtractive color. Yellow is commonly associated with gold ...
Green is a color on the spectrum of visible light, located between blue and yellow. It is evoked by light with a predominant wavelength of roughly 495-570 nm. In the subtractive color system, used in painting and color printing, it is created by a combination of yellow and blue, or yellow and cyan ...
Blue is the colour of the clear sky and the deep sea. It is located between violet and green on the optical spectrum. Surveys in the U.S. and Europe show that blue is the colour most commonly associated with harmony, faithfulness, confidence, distance, infinity, the imagination, cold, and sometimes with sadness.
Do nanometers help?
(I found a file on my computer with the above title. Pages 215-218 of what? The notes are probably from when I was researching Making Senses back in 2006... but the actual source? Possibly Folk Taxonomies in Early English (Anderson). Dunno. Anyway, here are my favourites.)
Synaesthesia is when you, for example, "see" the printed number 5 as green, and 2 as green. Or hear C-sharp as blue. I swear I remember reading about an experiment where - when a synaesthesiac sees the number 5 as red - the number 5 is also printed in red. And the resulting colour: HYPER-RED.
But I've been combing The Phenomenology of Synaesthesia (Ramachandran and Hubbard) which is the go-to paper on such questions (for example,
Does it matter whether the letters are upper or lower case? Yes it does)... and I can't find anything. Am I mis-remembering?
Finally: A list of fictional colours.
Plaid is one of the colors outside of the natural human spectrum visible to large intelligent arachnids in Vernor Vinge's novel A Deepness in the Sky. Cracking book that.