(Irregular preterit, past participle: overlaid).
To put something on top of something else; SYN. cover.

A covering either permanent or temporary: as an ornamental veneer; a decorative and contrasting design or article placed on top of a plain one; a transparent sheet containing graphic matter to be superimposed on another sheet

1. A section of a program designed to reside on a designated storage device, such as a disk, and to be loaded into memory when needed, usually overwriting one or more overlays already in memory. Use of overlays allows large programs to fit into a limited amount of memory, but at the cost of speed.
2. A printed form positioned over a screen, tablet, or keyboard for identification of particular features. See also keyboard template.

1. In computer graphics, to superimpose one graphic image over another.
2. In video, to superimpose a graphic image generated on a computer over video signals, either live or recorded.