The generalized diameter is the greatest distance between any two points on the boundary of a closed figure. The diameter of a subset of a Euclidean
space
is therefore given by

For a solid object or set of points in Euclidean -space, the generalized diameter is equal to the generalized
diameter of its convex hull. This means, for example,
that the generalized diameter of a polygon or polyhedron
can be found simply by finding the greatest distance between any two pairs of vertices
(without needing to consider other boundary points).

The generalized diameter is related to the geometric
span of a set of points.