A palindrome is a word, phrase, number, or other sequence of symbols that reads the same backwards as forwards. The word derives from Ancient Greek. It means: "a word or line that reads the same backward and forward," (1620s), from Greek palindromos "a recurrence," literally "a running back." Second element is dromos "a running"; the first is palin "again, back," from PIE *kwle-i-, suffixed form of root *kwel- (1) "revolve, move round." PIE *kw- becomes Greek p- before some vowels.