garnet: the colour of the pomegranate, a vivid red
ETYMOLOGY: French grenat < Latin granatum (pomegranate)
It can be heard in Eskenazi’s song „I Want You to Wear Yellow“ (1938)
I don’t want the garnet ones you usually wear anymore
wear your yellow ones, which suit you wonderfully.
“γρενά” refers to the grená colour, which is already well known, though.
Should this also be included in the Glossary or not?
Anyway, just for fun, I asked my younger son, who’s in his final year of secondary school, and he was completely stumped as to whether it was “grena” or “gkrena” 
The colour gkrená has been known for ages! I even have a gkrená blouse! But grená, on the other hand, is an unfamiliar word.
Hmm, men generally aren’t very good with unusual shades. I wonder what a girl of that age would say if you asked her?
I’ll ask and report back!
But we didn’t even get into the nuances with the son! It’s just a word…
Hmm… So perhaps not “since way back” but simply “back then”?
[I’ve told you I’m at an arts school, right? Well, once a colleague of mine—a literature teacher who had only just joined us and had spent all the previous years in mainstream schools—said to us:
—So, what’s the deal with all the artists here?
—Why?
—Well, I tell them, “Right, children, open the green book.” “Which green book, miss?” “The green one, our regular textbook! There, that one!” “Ahhh, you mean the petrol-blue book, miss?”]
Still, it’s incredible how many words—among those we suggest here in the Glossary and reject as “well-known”—are unknown to most of the people around us.
And I don’t mean just the younger generation.
Exactly! Green is one thing, petrol blue is another, seafoam is another, lime green is another, and so on. I have a nephew who’s an architect: “Nice blue jumper,” I tell him!
“It’s not blue,” he says, “it’s aqua!”
What can you say to him???
But as a word, they’d only know it if they’d had anything to do with clothes, fashion or set design. I only associate grená with clothing too.