Science fiction - and the correct shortcut is 'sf' - uses actual scientific facts or theories for the source ideas or framework of the story. It has some scientific content, however speculative. If it breaks a law of physics, it knows it's doing so and follows up the consequences. If it invents a society of aliens, it does so with some respect for and knowledge of the social sciences and what you might call social probabilities. And some of it is literarily self-aware enough to treat its metaphors as metaphors.
Ursula K. Le GuinThe borderline between prose and poetry is one of those fog-shrouded literary minefields where the wary explorer gets blown to bits before ever seeing anything clearly. It is full of barbed wire and the stumps of dead opinions.
Ursula K. Le Guin