Employee turnover refers to the rate at which employees leave a company and are replaced by new hires. It is typically measured as a percentage of the total number of employees in a given time period. High employee turnover can be an indication of issues such as low job satisfaction, poor working conditions, or inadequate compensation and benefits.

Example
A company experiences a turnover rate of 25% in a year, meaning that 1 out of 4 employees left the company and were replaced by new hires.