You would need to unpack that a bit. English allows nouns to be used as though they are adjectives, but that wouldn't work in Latin.
A dining room floor is a floor for a dining room. Or it might be a floor that is part of a dining room. The genitive construction is also used for a part of a whole.
Pavimentum triclinii habet.
I agree with your translation, but just to take your point a bit farther (that we need to "unpack" the meaning of the sentence in order to construct it in Latin), I think we could also use the following logic:
A dining room floor is a floor in a dining room. Let's use an ablative of place where:
pavimentum in triclinio habet.
All of which reinforces the fact that Latin is its own language, with its own idioms, its own style, etc.; it is not simply the way that ancient Romans spoke English. :-)
[Edit: fixed typo: lets --> let's]
Excuse me, but has anyone else noticed anything odd about this course?
First of all, Duolingo introduces a course in Latin, a dead language. This is strange in itself, as Duolingo is a practical language learning platform, not an academic institution.
Secondly, the creators have made very little effort to explain the target language's grammar. Instead, they seem obsessed with the dumping of (preferably fatty) fish on easily accessible surfaces such as floors and tables.
Thirdly, a disproportionate number of commenters have profile pictures featuring cats.
What is going on here?
Unfortunately, the course makers won’t lose much time explaining to you the cultural interest of such a sentence, so you can die in your ignorance, wondering why it is so relevant to know such an expression, which occur to be totally pointless if you are not brought in to knowledge.
Both "triclinium" and "pavimentum" are neuter, which means the nominative and the accusative look the same.