Planes
- Altitude Plane
- Bundle of Planes
- Cone-Plane Intersection
- Conic Section
- Coordinate Plane
- Coplanar
- Coplanarity
- Cox's Theorem
- Cross Section
- Cylinder-Plane Intersection
- Cylindric Section
- Dihedral Angle
- Director
- Ellipsoidal Section
- Euclidean Plane
- Half-Plane
- Hessian Normal Form
- Hyperplane
- Inner Quermass
- Isoclinal Plane
- Line-Plane Intersection
- Mediator
- Monge Point
- Monge's Tetrahedron Theorem
- Normal Plane
- Osculating Plane
- Parallel Line and Plane
- Parallel Planes
- Perpendicular
- Plane
- Plane Division by Lines
- Plane-Plane Intersection
- Point-Plane Distance
- Projection Theorem
- Sheaf of Planes
- Spheric Section
- Spheroidal Section
- Tangent Plane
- Toric Section
- Torus-Plane Intersection
- Tritangent