What is what does retain mean?

To retain means to keep or hold on to something. It can refer to physical objects that are kept for future use or to concepts, ideas, or memories that are held onto in one's mind. It can also refer to the act of maintaining or preserving something, such as a reputation or a relationship. In the business world, retaining customers refers to keeping them coming back and maintaining their loyalty. Similarly, retaining employees refers to keeping them on staff and retaining their services. Retention can also refer to the process of preventing or slowing down the loss of something, as in the retention of water in a dam.