A mockup is a static wireframe that features user interface styles and details to show a model of what the page will look like on the user end. A good way to think of it is that a wireframe is a blueprint and a mockup is a visual model.
What is a Mockup?
A mockup is a static visual layout of a user interface for an app or website that shows how buttons, images, and text will be laid out on the screen. It is used to present information in static form in front of a wireframe which is used to show the functionality of the page and not the actual look of it. A mockup is also used for showing clients different colors and layouts and styles that can be used when creating visuals on a page. Mockups typically include (but are not limited to) colors, graphics, typography and fonts, stylized buttons, navigation buttons or graphics, and spacing.