  A definition of metastable states applicable to arbitrary finite state Markov
processes satisfying detailed balance is discussed. In particular, we identify
a crucial condition that distinguishes genuine metastable states from other
types of slowly decaying modes and which leads to properties similar to those
postulated in the restricted ensemble approach \cite{pen71}. The intuitive
physical meaning of this condition is simply that the total equilibrium
probability of finding the system in the metastable state is negligible. As a
concrete application of our formalism we present preliminary results on a 2D
kinetic Ising model.
