>>281214390So in ye olden Japan you kind of had four colours; black, white, red, and blue/green and everything kinda fit into those four is how I remember hearing it. I forget whether it was blue or green as the 'main' one or if it even really worked like that but it's kinda hard to translate it without picking a specific one so please excuse me.
Traffic lights are sill ao but it is mostly blue these days.
Now that I think about it, those four in Japanese are kuroi, shiroi, akai, and aoi but every other colour is kinda 'different'. Green is kinda the same word as greenery, orange and pink are in English, brown and yellow are both basically named "[thing]colour", and purple (and green) are both kind of nouns rather than adjectives. So those four still are kinda special huh, that's neat.