A Palindrome is a word that read the same in both directions: forward and backwards. Examples are pup and nun. Its origins date back to at least 79 A.D. Palindromes are also called Sotadics, after the poet Sotades. He used palindromes frequently in his satirical poetry.
Early palindromes reversed the words and not the letters. some reorder complete words instead of each letter. Another form consists of words which contain symmetrical letters that look the same when turned upside down. In languages which employ a writing system other than an alphabet, a palindrome is still what it is - a sequence of characters from writing system that remains the same when reversed.