overlay

/ˈəʊvəleɪ/ noun [C]

Definition

› something such as a transparent layer or image that can be put over something else, for example to add information or show a relationship between two things: The printer is also able to add a watermark or overlay.

› information, data, ideas, etc. that are added to existing information: The phone codes could be changed completely, or by an overlay that adds a second area code.

(Definition of overlay noun from the Cambridge Business English Dictionary © Cambridge University Press)