You read the story online every so often about how the ancient Greek's couldn't see blue. And I always shook my head at it as some silly thing and nuance of linguistics, but tonight my brain just clicked on it and it made sense to me.
English has plenty of words for colors: Yellow, Blue, Green, Brown, Red, Black, Orange and Violet. (The colors in an 8-pack of crayons.)
And yet there are still more colors: black, blue, blue green, blue violet, brown, carnation pink, green, orange, red, red orange, red violet, violet (purple), white, yellow, yellow green, yellow orange. (Yup, 16-pack.)
Did these 8 new colors not exist previously? No, they just weren't named. We've identified arbitrary locations in a color wheel and assigned words to them. I guarantee other cultures and other people have identified colors and shades which English has no word for aside from #A82065 (a hex code I just made up on the spot and which turns out to be a lovely pink shade.)
So, the Greeks somehow decided to avoid giving blue its own name, but instead folded it into greens - my brain clicked on it tonight and I get it.
Well... so I decided to know more, and so I googled it and found this blog entry (take it with a grain of salt).
More specifically: yes, you can say 'blue' in ancient Greek. More precisely, Greek has words for the area of the colour palette that English calls 'blue'. But English 'blue' covers a huge region of the palette. Greek splits it into multiple smaller regions: glaukos for lighter, non-vivid shades; kyaneos for darker non-vivid shades ranging to black; porphyreos for vivid shades ranging from blue to violet to ruby, but also for less vivid shades in the middle of that range (light magenta, pink); lampros for metallic-silvery-azure. Yes, ancient sources do mention sky colour: it's glaukos or lampros. It's just that Homer doesn't mention the sky's colour (and why would he).
Colors and language. It's complicated.