A wireframe is a low-fidelity visual representation of a website or app's user interface that is used to communicate the layout, hierarchy, and functionalities of a product. Wireframes are typically created early in the design process and are used to get a basic understanding of how the product will look and function. They are usually simple, stripped-down versions of the final product that focus on the structure and layout of the interface, rather than visual design elements such as colors and fonts.