A mockup is a high-fidelity visual representation of a product or feature that is used to demonstrate its appearance and functionality. Mockups are often used in the design process to get a better understanding of how the final product will look and work, and can be created using tools such as Photoshop, Illustrator, or Sketch. Mockups can be static, showing the product at a single point in time, or interactive, allowing users to click or hover to see different states or views.