Translation:Akşam yemeği zamanı.
Isn't this just a noun phrase? To me, it seems equivalent to "dinner time" not "it is dinner time". If it is the latter, which is the translation given here, and the subject and copular are implied, is this structure common? Making " kedi", for example, a possible sentence meaning "it is a cat".
When two nouns are together, the second one obligatorily receives the 3rd person possessive suffix.
Akşam + yemek = akşam yemeği
[Akşam yemeği] + zaman = akşam yemeği zamanı