why not "bahçesiye" ? going to the garden would be "bahçeye gidiyouruz",isn't it ?
when noun already has other endings the buffer sound y becomes n instead. it's also true for accusative form.
So in this case, is it the "-si" suffix on "bahçe" that is causing the buffer "y" to turn into an "n"?
It denotes a connection between the two nouns in a noun compound. So 'fauna garden' or 'garden of fauna' translates to hayvanat bahçesi
So, hyvanat = hyvan + at + bahçesine (= bahçe +si + [n]e)? In other words, the nominative form of zoo is Hayvanat bahçesi? And in English, there is a term "zoological garden" although it is generally shortened to "zoo."
The nominative form of zoo is indeed hayvanat bahçesi, but I don't thinkt hat hayvanat is made up of hayvan and -at inside Turkish - I think the two words hayvan (animal) and hayvanat (zoology) were both borrowed in parallel from Arabic. And so yes, a hayvanat bahçesi is a "zoology garden" - pretty much the same as a "zoological garden".
You are right this term is derived from arabic language حيوانات it sounds like hyawanat