"The color of the peach juice."
Translation:Το χρώμα του χυμού ροδάκινο.
Please let me know if I have the correct understanding, when an item is made up of 2 words, like in this case, ο χυμός ροδάκινο, only the first part changes ending? and it becomes του χυμού ροδάκινο.
Yes because there is an omitted (με/από) between χυμός ροδάκινο so ροδάκινο always stays in accusative case. It's ο χυμός (από) ροδάκινο, του χυμού (από) ροδάκινο, τον χυμό (από) ροδάκινο, χυμέ (από) ροδάκινο.
Ah I see. It is something I never would have thought of. Thanks so much for the info. What if it is a 2-word item without preposition? Would both word have to change to genitive ending? For example, words like "grocery store" construction in English.
Another phenomenon I noticed is that του, της, των sometimes get omitted in genitive case. Can you explain more about that?
This discussion has a lot of info on the matter: https://www.duolingo.com/comment/17530852 . Hope it answers both of your questions!! :) in case it's too much: here is the sum-up: when a noun characterizes another noun, it's most of the time ok to put it in genitive WITHOUT article. So, orange juice=Χυμός πορτοκάλι (an omitted από is between them) or χυμός πορτοκαλιού. So the characterized noun had whatever case is required, but the characterizing one is always in genitive/nominative (if a preposition is omitted). But of these different ways of putting the characterized noun, sometimes one of them is preferred (or maybe a compound word) so this will solve itself through learning.