You got that right! See here: http://www.etymonline.com/index.php?term=cosmos&allowed_in_frame=0 (This is one of my favorite sites.)
Interesting that this course requires "a piece of jewellery" for κόσμημα (single) but rejects "the pieces of jewellery" for τα κοσμήματα. How would a native speaker refer to multiple items of jewellery then (like a collective noun for a gem necklace and a gemstone ring)?
"Jewelry is a singular collective noun. Whether a person is wearing one piece of jewelry or a dozen is irrelevant; jewelry is the word to use either way. Its plural is jewelries, but most writers would use the phrase pieces of jewelry instead."
(Pieces of jewelry has been added now.)
I think that the word "jewelry" without the article "the" should also be an acceptable transaction.
If the Greek had just " κοσμήματα" then you would write only "jewelry" that's the best way to learn. Since there is no context, not even a sentence there is no reason to change the usage. This is just here to help you learn vocabulary. Try to follow the exercises as they are.
Thank you for your quick response. But, and please don't take this negatively because I don't mean it that way, but Duolingo doesn't always follow that model. Sometimes the answer expected is literal, even if it sounds (or is) wrong in English, and other times the translation wanted, is how it would be said in English. If Duolingo were consistent on this it would make things easier and avoid a lot of confusion and frustration on the part of the learner. Or, maybe Duolingo could put some kind of marker in the question letting the user which of the two is called for in a given question. (If not obvious) Or, accept both translations. Just suggestions.
Your contributions are appreciated and no negativity is evident. Yes, I can understand that there is are inconsistencies in Duolingo expectations.
"...some kind of marker in the question letting the user which of the two is called for in a given question.
My advice is to follow the Drop Down Hints which give the expected reply for each sentence which I think would qualify as a marker.
"Or, accept both translations.
We always accept alternatives that can then be discussed in the Forums. We have some seemingly simple sentences with hundreds of ...yes even thousands of possible alternatives.
But the only way to have a constructive course is to have the main translation conform to certain standards that as I said are found in the Hints.
These are the regulations set down by the Duolingo Administration
I try to avoid pressing the underlined words because I don't want to be given the answer. Θέλω να μαθαίνω ελληνικά γιατί η γυναίκα μου είναι από την Ελλάδα καί μέσα(;) Καλοκαίρι, μένουμε εκεί.