What is an Overlay?

Overlay refers to a graphical user interface (GUI) element that is placed on top of another GUI element, such as a window or a button. An overlay can be used to provide additional information or functionality to the underlying element, and can be moved or resized independently of the underlying element.

In computer graphics, an overlay is a graphical object that is superimposed over another object. Overlays are commonly used in video editing software to add text or other graphics to a video clip. They can also be used in web design to add interactive elements to a website, such as drop-down menus or tooltips.

Overlay can also refer to a layer of material that is applied over another surface, such as a layer of paint over a wall or a layer of varnish over a piece of wood. In this context, the term "overlay" is often used interchangeably with "coat" or "layer."