Novum (Latin for new thing) is a term used by science fiction scholar Darko Suvin and others to describe the scientifically plausible innovations used by science fiction narratives.
He argues that the genre of Science Fiction is distinguished from Fantasy by the story being driven by a novum validated by cognitive logic. This means that the hypothetical 'new thing' which the story is about can be imagined to exist by scientific means rather than by magic.
References
Novum Wikipedia(Text) CC BY-SA