misconception - an incorrect conception

bubble - an impracticable and illusory idea; "he didn't want to burst the newcomer's bubble"

ignis fatuus, will-o'-the-wisp - an illusion that misleads

wishful thinking - the illusion that what you wish for is actually true

fiction - a literary work based on the imagination and not necessarily on fact

science fiction - literary fantasy involving the imagined impact of science on society

imagination, imaginativeness, vision - the formation of a mental image of something that is not perceived as real and is not present to the senses; "popular imagination created a world of demons"; "imagination reveals what the world could be"

pipe dream, dream - a fantastic but vain hope (from fantasies induced by the opium pipe); "I have this pipe dream about being emperor of the universe"

fantasy life, phantasy life - an imaginary life lived in a fantasy world

fairyland, fantasy world, phantasy world - something existing solely in the imagination (but often mistaken for reality)