ELI5: Explain Like I'm 5

Octahedron

An octahedron is a shape that has eight sides, like a stop sign. Each side is made up of two triangles that are connected, so it looks like a 3-dimensional star. It has six points, and all of the lines joining the points are the same length. Octahedrons are used in many different types of structures, like buildings and spacecrafts.