Is there an official term for the portion of the viewport that is currently visible?

Question

It recently occurred to me that there might be a technical term which would distinguish the view port (defined in the web context as 'the region within the browser that actually displays the web page') from the portion of the view port that is currently visible. This would be useful if one wanted to talk about a portion of the screen that is currently visible on zoom. Does anyone know if there is such a term?

Answer 1

As it turns out, the term 'viewport' is ambiguous and can refer to one of two distinct concepts-- 'layout viewport' and 'visual viewport'. An overview of this important difference can be found here: https://developers.google.com/web/updates/2017/09/visual-viewport-api as well as in the following answer Difference between visual viewport and layout viewport?.

To make a short story shorter, the viewport is essentially the height and width of the screen when on 100% zoom. The visual viewport is the portion of the layout that is currently visible to the user. This could (and often is) smaller than the overall layout width and height. In the diagram, I originally posted you might imagine a smaller square/rectangle inside of what is labeled to 'viewport.' This smaller rectangle would be the visual viewport and what is labeled 'viewport' would technically be the 'layout viewport'.