semordnilap

noun

Etymology: A reverse spelling of palindromes. "Semordnilap", according to author O. V. Michaelsen in his 1997 book Words at Play, was probably first used by recreational linguist Dmitri Borgmann, cited by Martin Gardner in the revised edition of Charles Carroll Bombaugh's Oddities and Curiosities of Words and Literature (1961) http://books.google.com/books?id=f4kNAQAAIAAJ&q=borgmann. The underlying concept (but not the term) is found at least as far back as Lewis Carroll's Sylvie and Bruno (1889). Semordnilap is also autological; that is, it is a self-describing word, as the word semordnilap is itself a semordnilap.

1. A word, phrase, or sentence that has the property of forming another word, phrase, or sentence when its letters are reversed. A semordnilap differs from a palindrome in that the word or phrase resulting from the reversal is different from the original word or phrase.

   “[He] then goes on to credit us with giving him some of the best examples of semordnilaps.”

   “This song is a semordnilap. It can be played forward and then sounds different when it is played backwards.”