16-Cell
A finite regular 4-D Polytope with Schläfli Symbol 
andVertices which are the Permutations of (
, 0, 0, 0).
- Nöther
- Obelus
- Object
- Oblateness
- Oblate Spheroid
- Oblate Spheroidal Coordinates
- Oblate Spheroidal Wave Function
- Oblate Spheroid Geodesic
- Oblique Angle
- Oblong Number
- Obstruction
- Obtuse Angle
- Obtuse Triangle
- Ochoa Curve
- Octacontagon
- Octadecagon
- Octagon
- Octagonal Number
- Octagram
- Octahedral Graph
- Octahedral Group
- Octahedral Number
- Octahedron
- Octahedron 5-Compound
- Octahemioctacron