retainer
1. re.tain.er \ri-'ta--n*r\ n [ME reteiner act of withholding, fr. reteinen + AF -er (as in] weyver waiver) 1: the act of a client by which he engages the services of a lawyer, counse lor, or adviser 2: a fee paid to a lawyer or professional adviser for advice or services or for a claim upon his services in case of need 2. retainer n [retain] 1: one that retains 2a: a person attached or owing service to a household; esp : ( MSER VANT 2b: EMPLOYEE 3: any of various devices used for holding something
Webster's English Dictionary