The term "mock-up" refers to a physical or digital representation of an idea, design, or product. It is typically used in the context of creating prototypes for products and designs before they are finalized and produced on a larger scale. A mock-up can be anything from a simple sketch or drawing to a full-scale model made out of materials such as cardboard, foam, or plastic. The purpose of a mock-up is to give designers and developers an opportunity to test and refine their ideas before committing resources to the final product. In essence, it's a way to experiment with different designs, layouts, and features in order to find the best solution for the problem at hand.