Wikipedia: Speculative fiction

In some contexts, it has been used as an inclusive term covering a group of fiction genres that speculate about worlds that are unlike the real world in various important ways. In these contexts, it generally includes science fiction, fantasy, horror fiction, supernatural fiction, alternate history, and magic realism. The term is used this way in academic and ideological criticism of these genres, as well as by some readers, writers, and editors of these genres. In these contexts, the term does not imply an opinion about the relative merits of any of the genres it includes.[…]

In other contexts, the term has been used to express dissatisfaction with what some people consider the limitations of science fiction per se. For example, in Harlan Ellison’s writing, the term may signal a wish not to be pigeonholed as a science fiction writer, and a desire to break out of science fiction’s genre conventions in a literary and modernist direction. Some readers and writers of science fiction see the term as insulting towards science fiction, and therefore as having negative connotations.

c.f. New Weird and Magic Realism