In
projective geometry, a
von Staudt conic is the point set defined by all the absolute points of a polarity that has absolute points. In the
real projective plane a von Staudt conic is a
conic section in the usual sense. In more general
projective planes this is not always the case.
Karl Georg Christian von Staudt introduced this definition in
Geometrie der Lage (1847) as part of his attempt to remove all metrical concepts from projective geometry.