Also: Gotta love how someone downvoted this simple observation. Go back to Reddit, whoever you are.
Appears to be an Asian and European term.
So I simplified a bit. Overall turnover is the same as revenue. Usually turnover is referred to as a ratio of accounts payable actually paid in a period or stock sold in a period.
Personnel turnover is also not an absolute number but a ratio of people to people leaving. So in this case turnover is the same as they are ratios but for personnel rather than widgets.
Hopefully that makes sense.