Okay kiddo, have you ever seen a knife or a sword? A prismatic blade is kind of like that, but it's shaped in a really cool and interesting way.
See, instead of being straight and smooth like a regular knife, a prismatic blade has lots of little angles and points all over it. This makes it look really cool, but it also makes it very strong and sharp.
Imagine a regular knife as a flat piece of paper, but a prismatic blade is more like a piece of paper that you've folded up in a lot of different ways to make it really strong.
People use prismatic blades for all sorts of things, like cutting wood, metal, or even food! They're very versatile and can do a lot of different jobs. But you have to be careful when using them, because they're so sharp that they could easily hurt you if you're not careful.
So that's what a prismatic blade is, kiddo - a really cool and strong type of knife or sword that has lots of little angles and points on it!