``The'' Griffiths point is the fixed point in Griffiths' Theorem. Given four points on a Circle and a line through the center of the Circle, the four corresponding Griffiths points are Collinear (Tabov 1995).
The points
See also Gergonne Point, Griffiths' Theorem, Incenter, Oldknow Points, Rigby Points
References
Oldknow, A. ``The Euler-Gergonne-Soddy Triangle of a Triangle.'' Amer. Math. Monthly 103, 319-329, 1996.
Tabov, J. ``Four Collinear Griffiths Points.'' Math. Mag. 68, 61-64, 1995.