Above the Fold
The immediately viewable area of a Web page when it first displays.
The amount of content displayed depends on the resolution of the screen. The higher the resolution, the more that is viewable, but the smaller the text and images.
It is a principle of good Web site design to place important design elements above the fold, usually placing in pre-defined content zones according to purpose, with navigation buttons in the left column or along the top, and ads usually in the right column.