  Crude comparison between four alternative proposals for the very definition
of a wormhole is provided, all of which were intended to apply to the dynamical
cases. An interesting dynamical solution, based upon large scale magnetic
fields, is used for the comparisons. Such solution goes beyond the perfect
fluid approximation due to an anisotropic pressure component, bringing to the
fore some unsuspected features of those definitions. Certain notions as
reversible traversability are claimed as a way to select among those
definitions the best suited one to represent our intuition of what a wormhole
solution is expected to be.
