When I was growing up during the late 70s/early 80s this was the meaning I understood for "hifi".

ie anything that sounded better than your average transister radio.

stuff has moved on since then though and modern kit is capable of producing a raesonable  soundstage.......which it wasn't  (IME) during the 70s.

So, for my money Hifi ( a bit like, dare I say it         , religion) its what ever it means to YOU.

IMO.

Yes I didn't think Mike would be far away with some figures!

only kidding!