Wireframe

A wireframe is a simple, stripped-back sketch of a page or screen that shows where things go and how it works, before any colour, images or final styling are added. It uses plain boxes and labels to focus attention on layout and flow rather than looks.

It is like an architect's rough floor plan: it settles where the rooms and doors sit before anyone picks the paint. Wireframes matter because they make it quick and cheap to test and change a design early, when reworking an idea costs minutes rather than the days it takes once everything is built.