STORY TIME: I was introduce to this terminology when I first introduced to Linux. It took me some time to absorb the idea completely. But now I think I have understood it…
Below given images are good analogy to explain mount points.
In figure — 1 if we plug in our phone charger in one of the points in extension board we assume that charger become the part of the system. So in figure -1 points 1 to 5 are called mount points of the extension thought which anything connected to those points became part of the extensions system.
In figure — 2 we are given a Linux file system. And suppose we want to access something from our flash drive using our Linux based OS. Then to actually access the content of the flash drive we need to make the flash drive part of our Linux file system. To do this Linux provide some points through which flash drive become virtually part of Linux , these points are called mount points.