What it is: The cursor or pointer is the way you tell your Macintosh what you want to select or modify.
You might think the cursor or pointer is relatively trivial but it’s your primary way to communicate with your Macintosh. If you want to select a command, you have to point at it using the mouse or trackpad. If you want to edit text, you’ll need to position the cursor where you want to edit the text either by using the keyboard or the mouse/trackpad. To keep from cluttering up your screen, the cursor/pointer is small, but that also means it’s hard to find.
Fortunately if you’re using El Capitan, there’s a simple way to find the cursor when you need it. Just grab the mouse and jiggle it around. In a few seconds, the pointer will suddenly appear much larger as the screenshot above shows. That way you’ll able to find the pointer easily. This also works with a trackpad too. Just press your finger on the trackpad and jiggle your finger to make the pointer appear temporarily larger so you can see it.
Just remember this shaking the mouse technique to enlarge the pointer only works with El Capitan, not with earlier versions of OS X so this should give you a reason to upgrade to El Capitan if possible.