Triangle Lines
- Antiorthic Axis
- Antipedal Line
- B-Line
- Brocard Axis
- Brocard Diameter
- Brocard Line
- Central Line
- de Longchamps Line
- Euler Line
- Exmedian
- Exmedian Point
- Extangent
- Fermat Axis
- Fontené Theorems
- Gergonne Line
- Griffiths' Theorem
- Intangent
- Isogonal Line
- Isoscelizer
- Isotomic Lines
- Isotomic Transversal
- Lemoine Axis
- Line at Infinity
- Nagel Line
- Orthic Axis
- Orthojoin
- Orthopole
- Parallelian
- Pedal Line
- Perspective Axis
- Perspectrix
- Philo Line
- Radical Axis
- Radical Line
- Simson Line
- Soddy Line
- Sondat's Theorem
- Symmedian
- Triangle Line
- Trilinear Line
- Trilinear Polar
- Trilinear Pole
- van Aubel Line