an impossibility presented and accepted by the reader, generally as a necessity that serves art, but sometimes as a triviality that gives an author great joy. The prime example is W.S. Gilbert's setting of The Pirates of Penzance Act I on the protagonist's birthday on a sunny day on the Cornwall shore, but in Act II we learn that the protagonist was born in Leap Year on the 29th of February, which would make that first Act setting an impossibility. My own use of this is when I set a split action scene, one in San Francisco and the other in Tuscany both simultaneosly at nightime. Triviality references (mine) include a cricket chirping in February in Georgia (I hang a lantern on that one) and (my favorite) a reference to a hummingbird by a Chinese character (in the 12th Cenury), an impossibility, because hummingbirds are indiginous to the Americas only.
Edward C. Patterson