retainer

Concise Oxford English Dictionary © 2008 Oxford University Press:
retainer/rɪˈteɪnə(r)/

▶noun

• 1 a thing that holds something in place.

• 2 a fee paid in advance to a barrister, in order to secure their services.

• 3 Brit. a reduced rent paid to retain accommodation during a period of non-occupancy.

• 4 a servant who has worked for a person or family for a long time.