The phrase "zoom function" refers to a feature that allows you to make something on your screen, such as text or images, appear larger or smaller by adjusting the magnification. Full definition
This one - hit wonder features a handy zoom function in which you hold down the right mouse button until it reaches its maximum optical reach or until you want to stop. (wolfsgamingblog.com)
You can interact with the tablet with the standard pinch zoom functions found in most tablets. (goodereader.com)
The pan / tilt / zoom function allows you to view your baby and their room from every angle. (omaby.com)