Torus

What is a Torus?

A torus is a special shape in geometry. It looks like a ring or a doughnut. You can make a torus by spinning a circle around a line that goes through the center of the circle but does not touch it.

Fun Shapes

There are different kinds of tori. If the line does not touch the circle, it makes a ring torus. If the line just touches the circle, it makes a horn torus. And if the line cuts through the circle twice, it makes a spindle torus.

Everyday Tori

Many things around us are shaped like tori. Think of swim rings, inner tubes, or ringette rings. They all have that ring-like form. A solid torus is a bit thicker, like in O-rings or bagels.

Flexible Shape

In topology, a torus is any surface that can be stretched into the shape of a ring torus. For example, the surface of a coffee cup and the surface of a doughnut are both tori. You can imagine building a torus by taking a flexible strip and joining its top to its bottom and its left to its right.

The word "torus" comes from Latin. It means something round, like a swelling or a bump.