A cone is a three-dimensional shape that has a circular flat base and slopes up smoothly to a single point at the top. Picture an ice cream cone or a traffic cone: wide at the bottom, tapering to a point at the top.

Cones appear everywhere in the world around you. Pine cones protect tree seeds. Volcanoes often form cone shapes as lava piles up around the opening. Party hats are usually cones. Even the cells in your eyes that detect color are called cone cells because of their shape.

In geometry class, you'll learn that cones are related to circles and triangles. If you “unroll” the sloped part of a cone, it forms a shape called a sector, like a pizza slice. The volume of a cone is exactly one-third the volume of a cylinder with the same base and height.

The word conical describes anything shaped like a cone. A wizard's hat is conical. So is a megaphone, which is cone-shaped to help project sound in one direction.