The Collaborative International Dictionary of English v.0.48:
Erewhon \Erewhon\ prop. n. [nowhere spelled backwards.] the fictitious land described in the novel Erewhon by Samuel Butler. [WordNet 1.5]WordNet (r) 3.0 (2006):
Erewhon n 1: a satirical novel written by Samuel Butler (1872) describing a fictitious land