Overlay/ˌəʊvərˈleɪ/ Definition 1 of 5Pro Tip 1/2Physical Layering Used to describe the act of placing one physical object on top of another. They chose to overlay the map with transparent paper for protection. Pro Tip 2/2Decorative Purpose Often used in the context of decoration or enhancing appearance. The artist decided to overlay his painting with a thin gold leaf.