Annulus (mathematics)

An annulus in math is like a fancy word for a donut. Imagine holding a donut in your hand. It has a hole in the middle and is a round shape. That's what an annulus looks like when you draw it on a piece of paper.

But instead of calling it a donut, math people call it an annulus. It's made up of two circles, one big and one small, that are connected by a curved line. This curved line is like the edge of the donut that goes around the hole in the middle.

So, if you ever see a picture of an annulus in math, just remember that it's like a donut with a big circle around a smaller circle.