A palindrome is a word, phrase, number or sequence of words that reads the same backwards as forwards. Punctuation and spaces between the words or lettering is allowed.
The longest single word palindrome in the English language, according to the Oxford English Dictionary, is the onomatopoeic 'tattarrattat', coined by James Joyce in Ulysses (1922) for a knock on the door. Fun fact: the longest palindrome in use today is said to be the Finnish word "saippuakivikauppias" which means soap stone vendor. Other fun palindromes include:
The word palindrome is derived from the Greek 'palin,' or "back" and 'dromos' or "direction." The actual Greek phrase alluded to the backward movement of the crab. Palindromes date back to about 70AD, when they were first found as a graffito buried in ash at Herculaneum.
This first known palindrome was in Latin and read "sator arepo tenet opera rotas" which means either:
The sower Arepo holds the wheels with effort.
The sower Arepo leads with his hand the plough.
Not exactly a grammatically correct sentence, but still pretty fun.
Palindromes were also found in ancient Greek and in ancient Sanskrit, so obviously people have been having quite a lot of fun with these unique words for quite a long time.
Another aspect of the palindrome is that it is able to reproduce itself. If a word is formed from the first letters of each word, and then from the second, the third and so on, it can then be arranged into a word square. A word square can be read in four different ways: horizontally or vertically from either top left to bottom right or bottom right to top left.
The most common of English palindromes are those that are read character by character, for instance, level, rotor and racecar. Character by character means that each character of the word matches, and the word can be spelled the same forwards or backwards.
"Madam I'm Adam" is a famous character by character palindrome. Palindrome examples also exist in phrases or sentences where punctuation, capitals and spacing are ignored. For instance "Sit on a potato pan, Otis". One of perhaps the most famous palindromes that exist in this form is "Able was I, ere I saw Elba."
Palindromes exist in names too; a past Prime Minister of Cambodia was named Lon Nol.
Some palindromes use whole words rather than letters, for example "First ladies rule the State and state the rule: ladies first." There, instead of each character matching, the whole sentence can be read backwards and forwards. The individual letters don't match, but the whole words do.
Palindromes aren't just a word game. They are also found in numbers and are studied in recreational mathematics. In fact, a palindromic prime is a palindromic number that is a prime number, such as 191 and 313.
Palindromes are even seen in molecular biology. Many molecular lengths between 4 and 8 nucleotides are palindromic as they correspond to nitrogenous sequences that read the same forwards as they do backwards.
Palindromes are seen in dates, and even in acoustics when a phrase once recorded and played backwards sounds the same. Palindromes are also found in modern and classical music pieces.
The purpose of using palindromes in your writing, whether it's words, whole sentences or numbers, is to create something entertaining. Consider them brain teasers. So go ahead and have fun with them!