Is it ensure, insure, or assure?
imaginative fiction dependent for effect on strangeness of setting (such as other worlds or times) and of characters (such as supernatural or unnatural beings). Examples include William Shakespeare's A Midsummer Night's Dream, Jonathan Swift's Gulliver's Travels, J.R.R. Tolkien's The Lord of the Rings, and T.H. White's The Once and Future King. Science fiction can be seen as a form of fantasy, but the terms are not interchangeable, as science fiction usually is set in the future and is based on some aspect of science or technology, while fantasy is set in an imaginary world and features the magic of mythical beings.