One century ago pioneering dielectric results obtained for water and
n-alcohols triggered the advent of molecular rotation diffusion theory
considered by Debye to describe the primary dielectric absorption in these
liquids. Comparing dielectric, viscoelastic, and light scattering results we
unambiguously demonstrate that the structural relaxation appears only as a
high-frequency shoulder in the dielectric spectra of water. In contrast, the
main dielectric peak is related to a supramolecular structure, analogous to the
Debye-like peak observed in mono-alcohols.