Definition of Verisimilitude
In a literary work, verisimilitude is likeness to the truth i.e. resemblance of a fictitious work to the real event even if it is a far-fetched one.
Verisimilitude ensures that even a fantasy must be rooted in the reality which means that events should be fantastic to the extent that readers consider them credible enough to be able to relate them somehow to their experiences of the real life.
And I thought it was a form of pasta :-)