Full Idea
A possible world is a complete determination of the truth-values of all propositions over a certain domain.
Gist of Idea
A possible world is a determination of the truth-values of all propositions of a domain
Source
Stephen Read (Thinking About Logic [1995], Ch.2)
Book Reference
Read,Stephen: 'Thinking About Logic' [OUP 1995], p.51
A Reaction
Even if the domain is very small? Even if the world fitted the logic nicely, but was naturally impossible?