A tetrahedron is a three-dimensional geometric shape that has four triangular faces, six edges, and four vertices. It is one of the simplest forms of a polyhedron and is classified as a type of triangular pyramid. The most common example of a tetrahedron is the regular tetrahedron, where all four faces are equilateral triangles of the same size. Tetrahedra can be found in various fields, including chemistry, where they represent the molecular structure of certain compounds, such as methane. In mathematics, they are studied in topology and geometry, and they can also be used in computer graphics and modeling to create complex shapes and structures.