Thank you. The tool to spot spelling mistakes will not catch those. 
I thought so. Thx for clarifying.
What is κύανος (and the adjective κυανός / κυάνεος), chopped liver?
Serious question: what about the word family I cited? Homer may never have used it, but Homer ≠ the totality of Ancient Greek speakers. As far as the point about Prussian Blue, consider smalt: Cobalt glass - Wikipedia.
Different periods of "ancient Greece’, it seems. But that word uses the modern term blue to describe a type of enamel often used on armor, which to us is Blue. The idea they could not SEE blue is bogus IMHO. In other words, they had words to describe blue things, but Ancient Greeks did not have a single word for the color “blue” as a standalone spectral hue.
Experts claim that languages tend to develop color words in a sequence—start with black and white, then red, yellow, green, and finally blue.
Does anyone seriously claim that? I’ve never heard of it. It’s, like you say, just a matter of how they classified colors. You might not have a word for, say, “orange,” but “red” and “yellow” can cover it. Of course it doesn’t mean they couldn’t see it, unless their biology was fundamentally different than ours.