retainer
/rɪˈteɪnə(r)/noun
1
- a thing that holds something in place护圈; 定位器：
a guitar string retainer.
吉他弦定位器。
1.1
- an appliance for keeping a loose tooth or orthodontic prosthesis in place（固定松动牙齿或矫正牙齿用的）固位体。
2
- a fee paid in advance to someone, especially a barrister, in order to secure or keep their services when required（尤指预付给律师的）聘用定金。
2.1
- Brit. a reduced rent paid to retain accommodation during a period of non-occupancy〈英〉（在不住期间为保留租房而付的）定金。
3
- a servant or follower of a noble or wealthy person, especially one that has worked for a person or family for a long time（尤指服务多年的）仆人, 随从; 跟班。