Some of the letters do, but not all of them.
In particular I wouldn’t expect many people to know the obscure ones like omicron, mu and nu.
Alpha, beta, gamma, detla and omega find use in commonly known terms.
Iota finds (somewhat uncommon) use as ‘a very small quantity’ and pi turns up in maths of course,
but beyond that I expect most people won’t be familiar with any of the other letters.
(Other letters like sigma, phi and tau turn up in maths,
but probably only the level of maths taught at college/uni level,
not something I’d expect the man on the street to know.)
Coincidentally ‘mesa’ is one of the words I was thinking of.
I can say categorically that I didn’t know what a mesa was until college when I wanted to know what Black Mesa was after playing Portal 2.
I would certainly hope most British students would learn what a loch is at primary school, even if they aren’t Scottish.
I expect even a fair chunk of American children have heard of Loch Ness thanks to its mythical monster, though whether they’d know what a loch is would be a different matter.
Some of the other things I was thinking of are words like glen, dale, fjord, inlet…
They’re not particularly uncommon geographical features,
but I’m not sure how many people would know those words.
And yet lots of people would probably know what swamps, canyons and glaciers are.
At the very least we can say they are all words that are in use,
it’s just a question of whether that use is ‘common’.
That makes sense.
In which case I’d expect ‘thine’ (“to thine own self be true”) and ‘thee’ (“fare thee well”) as well.
Though that does pose the conundrum of whether ‘mickle’ and ‘muckle’ should be words, since “many a mickle makes a muckle”…
What a minefield.
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