Incidence

• Archimedes' Axiom
• Archimedes' Lemma
• Archimedes' Postulate
• Cathetus
• Ceva's Theorem
• de Bruijn-Erdős Theorem
• Foot
• Hoehn's Theorem
• Menelaus' Theorem
• Monge's Circle Theorem
• N-Cluster
• Near-Pencil
• No-Three-in-a-Line-Problem
• Non-Archimedean Geometry
• Ordinary Line
• Ordinary Point
• Orthogonal
• Pascal's Theorem
• Pasch's Axiom
• Pasch's Theorem
• Perpendicular
• Perpendicular Bisector
• Perpendicular Bisector Theorem
• Perpendicular Foot
• Perpendicular Vector
• Self-Transversality Theorem
• Separation
• Steiner Set
• Sylvester-Gallai Theorem
• Sylvester's Line Problem
• Tetrastigm
• Urquhart's Theorem
• Vertical Tangent