  A possible universal definition for a nanostructured material based purely on
experimental data available in literature for a wide variety of physical
phenomena is proposed. It is suggested that for values of the ratio of sample
volume, V to that of the unit cell volume, Vc, 10^5- 10^6 the samples behave as
nanostructures. This is mirrored in the ratio of the number of particles in
sample, N to that in the unit cell, Nc. It is further proposed that the
transition to the nanophase from bulk is a phase transition in all cases
investigated. The nanophase should therefore be treated as a distinct phase of
matter, entirely in the quantum mechanical domain, and treated appropriately.
