Okay kiddo, do you know how sometimes when you’re drawing a picture or playing a video game, the edges of things look all jagged and rough? That’s because the computer is made up of tiny little squares called pixels that make the picture, and when it tries to draw a smooth round line, it can’t make a perfect circle with just little squares.
Multisample anti-aliasing is like a special tool that helps the computer make those jagged edges look smoother and less rough. It works by taking several pictures of the same thing but moving the camera (or the image) just a tiny bit each time. Then, it looks at all the pictures and does some tricky math to figure out which parts should be blurry and which parts should be sharp, to make the edges look smoother and more natural.
So basically, multisample anti-aliasing is like putting on a special pair of glasses that make everything look nicer and less bumpy, so your pictures and videos look better and clearer!