HPSC student: So when are the Middle Ages?
Me: More or less from 500 to 1500… give or take a couple of centuries and depending on local political conditions.
HPSC student: So when is the Medieval period then?
Me: same time. Medieval is an adjective, Middle Ages is a noun.
HPSC student: Oh. *HPSC Prof* told us we have to understand the difference.
Me: Perhaps she meant a grammatical difference?
HPSC student: No, she gave us different time periods and everything.