It's pretty common to be talking about the HRE, and hear "Which wasn't Holy, Roman, or an Empire". Why isn't the HRE considered Holy, Roman, or an Empire?

Voltaire has a lot to answer for about that particular political entity. More can always be said about the Holy Roman Empire if anyone would like to address themselves to that subject; for the meantime, here's some previous posts on this matter:

u/kieslowskifan considers the Voltaire quote and how well it applies;
u/Aethelric examines the empire-ness of the Empire;
u/YuaIsLife has thoughts on when it lost its empire-ness.