science fiction 
(abbreviation SF)
noun [mass noun]
Fiction based on imagined future scientific or technological advances and major social or environmental changes, frequently portraying space or time travel and life on other planets.He has composed for a variety of genres but science fiction, horror and fantasy stories dominate his filmography....
- The motif of alien beings peopling our planet is a very common one in science fiction.
- This very modern thriller has all the elements of science fiction combined with a racy thriller.