Is there a single word which means "of or relating to a particular era"? I am looking for a word which means that something is limited to a particular era, as opposed to being universal. Preferably it should be conjugated from the word era, but doesn't have to be.
As an example, things that only existed during the Stone Age, or practices that were only practiced before World War II, or beliefs that were prevalent before the Industrial Revolution, or technology which existed after the advent of computers, could be said to be [insert word here].
I have made several attempts to clarify what I am asking for, and I seem to be having trouble communicating. "Particular" can mean "an individual object, as contrasted with a universal" - see definition 11 here. I am looking for a word that says a noun belongs to any one era, as opposed to belonging to all eras. "Food" would not be described with this term, as "food" belongs to any era. "Automobile" would, as "automobile" only existed during the Modern Era and not before. "Uncharted territory" only existed in the era before satellite imagery (at least as far as Earth is concerned). I am not looking for a word which is confined to any one particular era. I am looking for a word which is confined to any one era in the set of all eras.