/rɪˈteɪnər/ – Noun
Definition: 1. hợp đồng với luật sư, ủy quyền cho luật sư bào chữa vụ án;
2. tiền thù lao ứng trước cho luật sư;
3. việc giữ lại.
A more thorough explanation: A retainer is a fee paid in advance to secure the services of a professional, such as a lawyer or consultant, for a specified period of time or for a particular project. It is a form of prepayment for future services to be rendered.
Example: The lawyer required a retainer fee from the client before starting work on the case.