I am not really a classicist, and I hope it’s OK to use these boards to get a very little help (one word’s worth of help!) from someone who is. I am currently translating and annotating the work of the 18th century Italian scientist Vitaliano Donati. In his book he gives an etymology (probably, I think, false) of the word “coral” as being derived from two Greek words which appear in his book like this:

… and which he glosses as meaning ornamento, e bellezza di mare — “ornament and beauty of the sea”.
The second word, ἁλός, is fine, it’s “salt” in the genitive, used to mean “of the sea”. The first word looks like κοςεῖν, which is just plain wrong, what’s a final sigma doing in the middle of a word?
But now the plot thickens. In the French edition of the book, the words appear like this:

Now the doubtful letter appears to be an 18th century typographer’s idea of a rho — I think. Which is all to the good, because Donati thinks he’s providing an etymology for κοράλλιον, which has a rho in it.
The problem with this is that κορεῖν does not, so far as I know, mean “ornament” or “beauty”. It is the infinitive of a verb meaning “sweep clean”.
To complicate things a little further, many people have suggested that κοράλλιον is derived from κόρη ἁλός — “daughter of the sea”. But if Donati was trying to refer to this etymology, how did he come to make such a gross mistake?
Well, it beats me. I’ve looked through Greek thesauruses for words meaning “ornament” and “beauty” that might have been misprinted as κοςεῖν or κορεῖν, and have drawn a blank. Now I can think of nothing to do but appeal to the wisdom, ingenuity, and kindness of others. Can anyone figure out what Donati meant to write, and why?
Anyone who can help will receive my eternal gratitude, and, if s/he likes, an acknowledgement if my translation ever comes to press.