What is the meaning of turnover?

noun

• The ratio of the number of workers that had to be replaced in a given time period to the average number of workers.
  • synonyms: employee turnover, turnover rate
• A dish made by folding a piece of pastry over a filling.
• The volume measured in dollars.
  • usage: "the store's dollar volume continues to rise"
  • synonyms: dollar volume
• The act of upsetting something.
  • usage: "he was badly bruised by the upset of his sled at a high speed"
  • synonyms: upset, overturn