When workers leave their jobs and are replaced by other workers, that's turnover. A totally different kind of turnover is a delicious baked good with a sweet filling.
If an economist is talking about turnover, she probably means the rate at which a business loses employees, or how many jobs they have to fill over the course of a year. If that same economist is placing an order at a bakery, she may instead mean the flaky, triangle-shaped pastry that's wrapped around a fruit filling. In the work world, having a lot of turnover is a negative thing. In the pastry world, a high rate of turnovers doesn't sound bad at all.