Superimposed is a term used to describe when one object is placed over another. It can be done in various ways, such as overlain, ATOP, or OVERLAID. Overlain is when an object is placed on top of another object and held there by its own weight. ATOP is when an object is placed directly on top of another object. OVERLAID is when an object is placed on top of another object and secured in place with adhesive or other means. All three of these terms describe the same concept of superimposing one object over another.