Speculative fiction

Speculative fiction is an umbrella genre encompassing every subgenre that departs from realism, presenting the fantastical, supernatural, futuristic or otherwise highly imaginative. Its subgenres include fantasy, science fiction, social science fiction, science fantasy, superhero, paranormal and supernatural horror, alternate history, magical realism, slipstream, weird fiction, utopia, dystopia, and apocalyptic and post-apocalyptic fiction. The term is often attributed to Robert A. Heinlein, who first used it in a 1947 Saturday Evening Post editorial as a synonym for science fiction and later said his use excluded fantasy; Judith Merril and other New Wave writers popularized it in the 1960s and early 1970s in dissatisfaction with establishment science fiction, and during the 2000s it came into wider use as a convenient way to describe a set of genres.

For writers it is the top-level shelf tag: fantasy, science fiction, horror and blends like science fantasy all sit inside it, making it the honest tag for stories that cross those lines.