Retainer
01
仆人, 侍从
a person working in the service of another (especially in the household)
02
保持器, 牙齿固定器
a device used to maintain the position of teeth after braces are removed
例子
After braces, Jenny wore a retainer to keep her teeth straight.
在牙套之后，珍妮戴了一个保持器来保持她的牙齿整齐。
After treatment, Alex got a clear retainer to wear discreetly.
治疗后，亚历克斯得到了一个可以谨慎佩戴的透明保持器。
03
酬金, 预付款
a fee charged in advance to retain the services of someone
