What
truth is stranger than, and:
Something that is not true.
It is something that is not true, but that is not a delusion, because the speaker of the untruth does believe it is true.
It is also
something that is not true, but that the speaker or writer of the untruth does not present as a truth (which would be a falsehood and/or a lie). If a writer publishes a work of fiction, and then asks that it be assigned a "fiction" designation, he is telling the reading public the truth.
Someone once asked a writer if it was "hard" writing fiction:
His answer, "No, it's actually one of two things: easy or impossible
The same could be said of writing nodes.