The line through a Triangle Vertex obtained by reflecting an initial line (also through a Vertex) about the Angle Bisector. If three lines from the Vertices of a Triangle are Concurrent at , then their isogonal lines are also Concurrent, and the point of concurrence is called the Isogonal Conjugate point.
See also Isogonal Conjugate
Johnson, R. A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle.
Boston, MA: Houghton Mifflin, pp. 153-157, 1929.