A clustering reaction in a homogeneous, supersaturated solution (solid or liquid)
which is
unstable against infinitesimal fluctuations in density or composition. The solution therefore
separates spontaneously into two phases, starting with small fluctuations and proceeding
with a decrease in the Gibbs energy without a nucleation barrier.
Source:
PAC, 1994, 66, 577
(Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations
1994))
on page 591