A wireframe is an early step in the design process of a website. Wireframes are a way of laying out the divisions (divs) on a web page. The different sections on a single page need to be arranged in a logical and visually appealing way. They also need to be usable and to not surprise users.
I am well versed in the popular 960 pixel grid system and other grid systems. I make wireframes for both the full-width and mobile versions of web pages.