# Corner overlay (mosca): what it is and how it works
> A mosca is a small graphic element fixed in a screen corner, such as an overlay ad or a TV channel’s on-screen logo.
URL: https://www.zorraquino.com/en/dictionary/advertising/fly.html

# Corner overlay (mosca)

In Spanish advertising jargon, a mosca (literally “fly”) is a small graphic element that stays fixed in a corner of the screen, such as an overlay ad on a website or a TV channel’s logo during broadcasts

What it means, how it is used and where it comes up, with its related concepts.

[The whole glossary](https://www.zorraquino.com/en/dictionary)

## What it is and how it works

Online, it is a small ad that overlays the content and stays in the same position as the person scrolls, unlike layer ads, which move around the screen. It belongs to the floating formats and, like them, can be annoying if it is not easy to close.

In television, the term refers to the semi-transparent channel logo that identifies the broadcast, known in English as a digital on-screen graphic or bug. By extension, it also describes brief advertising overlays in a corner of the screen during a programme or broadcast.

Also known as

Digital on-screen graphic, Bug, Corner ad

Topics

[Marketing and sales](https://www.zorraquino.com/en/dictionary/category/marketing-y-ventas)

## Related concepts

- [Floating ad formats](https://www.zorraquino.com/en/dictionary/advertising/floating-formats.html)
- [Layer ads](https://www.zorraquino.com/en/dictionary/advertising/layers.html)
- [In-page ad formats](https://www.zorraquino.com/en/dictionary/advertising/integrated-formats.html)