Zooming is the act of enlarging something (a document, an image, a map) to view it in greater detail. (DO NOT USE for questions about the Zoom communications platform; instead, use [zoom-sdk].)
Zooming in graphical user interfaces is a facility that allows users to change the scale of the viewed area in order to see more detail or less. Often, there is a facility that allows the user to move the zoomed area with respect to the overall item being viewed.