The term "vested" in general means "entitled" or "earned". When the term "vested" is used with respect to a retirement plan at work it typically means a certain period of time where an employee works for the employer and monies are contributed into the retirement plan for the employee where the employee is "entitled" to the retirement benefits as part of his or her employement.When an employee's retirement is "vested" it cannot be lost by the employee upon changing jobs.If your are an employee asking questions about an employer's retirement plan, you should first review the employee handbook and then speak to the human resources department if there are unanswered questions about it.Good luck.