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"Palindromes" redirects here. For the film, see Palindromes (film).

A palindrome is a word, phrase, number, or other sequence of symbols or elements that reads the same forward or reversed, with general allowances for adjustments to punctuation and word dividers. Famous examples include "Amore, Roma", "A man, a plan, a canal: Panama" and "No 'x' in 'Nixon'".

Composing literature in palindromes is an example of constrained writing. The word "palindrome" was coined from the Greek roots palin (πάλιν; "again") and dromos (δρóμος; "way, direction") by the English writer Ben Jonson in the 17th century. The Greek phrase to describe the phenomenon is karkinikê epigrafê (καρκινικὴ επιγραφή; "crab inscription"), or simply karkinoi (καρκίνοι; "crabs"), alluding to the movement of crabs, such as an inscription that may be read backwards.



A palindrome with the same property is the Hebrew palindrome, "We explained the glutton who is in the honey was burned and incinerated", (פרשנו רעבתן שבדבש נתבער ונשרף; perashnu: ra`avtan shebad'vash nitba'er venisraf), by Abraham ibn Ezra, referring to the halachic question as to whether a fly landing in honey makes the honey treif (non-kosher).

ו נ ש ר פ
ן ת ב ע ר
ש ב ד ב ש
ר ע ב ת נ
ף ר ש נ ו

Another Latin palindrome, "In girum imus nocte et consumimur igni" ("We go wandering at night and are consumed by fire", in which "In girum ire" is translated as "go wandering" instead of the literal "go in a circle", cf. Italian "andare in giro", "go strolling or wandering around"), was said to describe the behavior of moths. It is likely that this palindrome is from medieval rather than ancient times.

Byzantine Greeks often inscribed the palindrome, "Wash [the] sins, not only [the] face" ΝΙΨΟΝ ΑΝΟΜΗΜΑΤΑ ΜΗ ΜΟΝΑΝ ΟΨΙΝ ("Nīpson anomēmata mē mōnan ōpsin", engraving "ps" with the single Greek letter Ψ, psi), on baptismal fonts. This practice was continued in many English churches. Examples include the font at St. Mary's Church, Nottingham and also the font in the basilica of St. Sophia, Constantinople, the font of St. Stephen d'Egres, Paris; at St. Menin's Abbey, Orléans; at Dulwich College; and at the following churches: Worlingworth (Suffolk), Harlow (Essex), Knapton (Norfolk), St Martin, Ludgate (London), and Hadleigh (Suffolk).

Palindromes in Arabic language[edit]

Arabic language is an abjad; that is, only consonants are represented as letters. Vowels are not visible as letters. Instead, they can be represented using diacritics. Palindromes in Arabic are taken from letters (consontants) only, disregarding vowels that follow/proceed them. Examples are shown below.

In the Quran[edit]

  1. ربك فكبر (transl.: rabbaka fakabbir, [And] your Lord glorify) (Quran 74:3)
    The sentence reads rabbaka fakabbir. Here, reading the sentence backwards including vowels would not create a palindrome. However, taking out consonants only (which are here: r, b, k, f, k, b, r) can clearly create a palindrome.
  1. كل فى فلك (transl.: kullun fi falak, ... [but] each, in an orbit, is swimming) (Quran 36:40)
    Consontants are: k, l, f, y, f, l, k.

In Arabic literature[edit]

A poem credited to an anonymous writer[citation needed] contains a palindromic verse:

مودته تدوم لكل هول * وهل كل مودته تدوم

The verse transliterates to: mawaddatuhu tadumu likulli hawlin * wahal kullu mawaddatihi tadumu; and translates to: His cordiality lasts despite all calamities * but, will all of his cordiality last? Consonants are: m, w, d, t, h, t, d, w, m, l, k, l, h, w, [l], w, h, l, k, l, m, w, d, t, h, t, d, w, m; with [l] being the mid letter.

Palindromes in ancient Sanskrit[edit]

Palindromes of considerable complexity were experimented with in Sanskrit poetry.[1] Complex palindromes appear in the 19th canto of the 8th-century epic poem Śiśupāla-vadha by Magha. It yields the same text if read forward, backward, down, up, or diagonally:

sa- ka- ra- na- na- ra- ka- sa-
kā- ya- sā- da- da- sā- ya-
ra- sā- ha- vā- ha- sā- ra-
nā- da- vā- da- da- vā- da- nā.
(nā da da da da
ra ha ha ra
ya da da ya
sa ra ra sa)

(Note: a hyphen indicates a continuation of same word.) The last four lines are an inversion of the first four and are not part of the verse. They are included here only so that its properties may be more easily discerned, as the up-and-down reading depends on re-reading the text back up again in each column.

The stanza translates as:

[That army], which relished battle (rasāhavā), contained allies who brought low the bodes and gaits of their various striving enemies (sakāranānārakāsakāyasādadasāyakā), and in it the cries of the best of mounts contended with musical instruments (vāhasāranādavādadavādanā).

The same work (Śiśupāla-vadha) also contains stanzas in which each line is a palindrome, and stanzas that may be read backward to give a new stanza (semordnilaps). Such stanzas are also found in the earlier work Kirātārjunīya.

This Sanskrit poem was written by "nandi-ghanta kavis" in kanda style.

सारस नयना घन जघ

नारचित रतार कलिक हर सार रसा

सार रसारह कलिकर

तारत चिरनाघ जनघ नायनसरसा |

Palindromes in Tamil poetry[edit]

Palindromes are referred to in Tamil as "Maalai Maatru" (மாலை மாற்று). The earliest known palindromic verses (11 couplets) occur in the devotional poetry of the Shaivism saint Sambandhar who lived around the 7th Century C.E.

The first of these eleven verses runs thus:

யாமாமாநீ யாமாமா யாழீகாமா காணாகா

காணாகாமா காழீயா மாமாயாநீ மாமாயா

It refers to Shiva as the incomparable God, the one who plays the Veena, the beautiful one adorned with snakes, the one who destroyed Kama, whose abode is Sirkazhi, who also appears as Vishnu, and beseeches him (Shiva) to rid the devotee of impurities.

Palindromic verses are also to be found in Madhava Shivagnana Yogi's Kanchi Puranam (மாதவச்சிவஞானயோகிகள் காஞ்சிப் புராணம்) and in Mahavidvaan Meenakshi Sundaram Pillai's Thirunaagaik Kaaronap Puranam (மகாவித்துவான் மீனாட்சிசுந்தரம் பிள்ளை திருநாகைக் காரோணப் புராணம்).[2]

Palindromes in Persian[edit]

A famous example that most students in Iran have heard in literature classes is:

شکر بترازوی وزارت برکش

literally could be translated to "weigh the sugar with the ministry scale"


Character, word, or line unit[edit]

The most familiar palindromes, in English at least, are character-by-character: The written characters read the same backward as forward. Some examples of common palindromic words: civic, radar, level, rotor, noon, kayak, reviver, racecar, redder, madam, Malayalam, and refer. There are also palindromes where the unit of reversal is the word ("So patient a doctor to doctor a patient so") or line (as in the poem "Doppelganger" by J.A. Lindon). These are referred to as "word-unit palindromes" and "line-unit palindromes" respectively.[3] Word-unit palindromes were popularized in the recreational linguistics community by J.A. Lindon in the 1960s, but occasional examples in English are found from at least the 19th century, and several in French and Latin date to the Middle Ages.[4]


Palindromes often consist of a phrase or sentence, e.g.: "Eva, can I stab bats in a cave?", "Mr. Owl ate my metal worm", "Was it a car or a cat I saw?", "A nut for a jar of tuna", "Do geese see God?", "Ma is as selfless as I am", "On a clover, if alive erupts a vast pure evil, a fire volcano." "Dammit, I'm mad!", "A Toyota's a Toyota", "Go hang a salami, I'm a lasagna hog", and "A Santa lived as a devil at NASA". Punctuation, capitalization, and spacing are usually ignored, although some, such as "Rats live on no evil star", "Live on time, emit no evil" and "Step on no pets", include the spacing.

Famous English palindromes[edit]

Some well-known English palindromes are, "Able was I ere I saw Elba",[5] "A man, a plan, a canal - Panama!",[6] "Madam, I'm Adam" or "Madam in Eden, I'm Adam", "Doc, note: I dissent. A fast never prevents a fatness. I diet on cod"[7] and "Never odd or even". "Rise to vote, sir" was featured in an episode of The Simpsons.


Some people have names that are palindromes. Included are given names (Ada, Anna, Bob, Aviva), surnames (Harrah, Renner, Salas, Arora) or both (Eve, Hannah, Maham, Otto). Lon Nol (1913–1985) was Prime Minister of Cambodia. Nisio Isin is a Japanese novelist and manga writer, whose real name (西尾 維新, Nishio Ishin) is a palindrome when romanized using the Kunrei-shiki or the Nihon-shiki systems. (It is often written as NisiOisiN to emphasize this). Some persons have changed their name in order to make of it a palindrome (one example is actor Robert Trebor), while others were given a palindromic name at birth (such as the philologist Revilo P. Oliver or the flamenco dancer Sara Baras). Some names can be made part of a larger palindrome, like: "You have no name, Manon Eva Huoy!".

Palindromic names are very common in Finland. Examples include Olavi Valo, Emma Lamme, Sanna Rannas, Anni Linna and Asko Oksa.

There are also palindromic names in fictional media. "Stanley Yelnats" is the name of a character in Holes, a 1998 novel and 2003 film. Four of the fictional Pokémon species have palindromic names in English (Eevee, Girafarig, Ho-Oh, and Alomomola).

Molecular biology[edit]

Main article: Palindromic sequence

Restriction enzymes recognize a specific sequence of nucleotides and produce a double-stranded cut in the DNA. While recognition sequences vary widely, with lengths of between 4 and 8 nucleotides, many of them are palindromic, which correspond to nitrogenous base sequences between complementary strands, which, when read from the 5' to 3' direction, are identical sequences.


Main article: Palindromic number


The continued fraction of \sqrt{n} + \lfloor\sqrt{n}\rfloor is a repeating palindrome when n is an integer. The last palindromic year was 2002. There won't be another one until 2112.


A palindrome in which a recorded phrase of speech sounds the same when it is played backward was discovered by composer John Oswald in 1974 while he was working on audio tape versions of the cut-up technique using recorded readings by William S. Burroughs. Oswald discovered in repeated instances of Burroughs speaking the phrase "I got" that the recordings still sound like "I got" when played backward.[8][9]

In France, a more complex example has been identified with[citation needed] "Une slave valse nue" (a Slavic girl waltzes naked).

Classical music[edit]









Popular music[edit]

Musical content[edit]

Hüsker Dü's concept album Zen Arcade contains the songs, "Reoccurring Dreams" and "Dreams Reoccurring", the latter of which appears earlier on the album, but is actually the intro of the former song played in reverse. In a similar manner, The Stone Roses' first album contains the songs "Waterfall" and "Don't Stop", the latter of which is, in essence, the former performed backward. The 12" and CD formats of their single Elephant Stone feature the B-side "Full Fathom Five", which is an alternate mix of the title track played in reverse.

The title track of the 1992 album entitled UFO Tofu by Béla Fleck and the Flecktones is said by its composer to be a musical palindrome.

In 2003, the city of San Diego, California commissioned sculptor Roman DeSalvo and composer Joseph Waters to create a public artwork in the form of a safety railing on the 25th Street overpass at F and 25th Streets. The result, Crab Carillon, is a set of 488 tuned chimes that may be played by pedestrians as they cross the overpass. Each chime is tuned to the note of a melody, composed by Waters. The melody is in the form of a palindrome, to accommodate walking in either direction.[14]

The strings part in "Starálfur", from the album Ágætis byrjun by Sigur Rós, is a palindrome.

The song "You Can Call Me Al" by Paul Simon features a palindromic bass run performed by Bakithi Kumalo.

Progressive metal band Lazer/Wulf's 2014 debut album "The Beast of Left and Right" is palindromic with the musicians having reversed and synchronized elements of each song including riffs and lyrics.


The song, "I Palindrome I", by They Might Be Giants, features palindromic lyrics and imagery. The 27-word bridge is word-symmetrical.

"Weird Al" Yankovic's song, "Bob", from his 2003 album Poodle Hat, consists of rhyming palindromes and is a style parody the Bob Dylan song "Subterranean Homesick Blues". There is an accompanying video for the song which also parodies Dylan's video. Yankovic shows all of the palindromes on cue cards as they are being sung.

Baby Gramps is known for songs where the lyrics are made up of palindromes.

Names and titles[edit]

ABBA's song "SOS" is the only Billboard Hot 100 single to have both a title and a recording artist whose names are both palindromes.

The Grateful Dead's 1969 album Aoxomoxoa is a notable early use of a palindrome in the title of a popular music album.

In 1992, the grunge band Soundgarden released an EP called Satanoscillatemymetallicsonatas or SOMMS; the title is a palindrome and puns on the supposed connection between the Devil and heavy metal music.

On Boris and Sunn O)))'s collaborative album "Altar", the vinyl version included a full disc, double-sided bonus track entitled "Satan Oscillate My Metallic Sonatas" (in reference to the Soundgarden EP of the same name), in which the various instruments (mainly guitars) are introduced one at a time on side one, and then fade out in reverse order on side two. Kim Thayil of Soundgarden appears on this track.

The Fall of Troy made a song with the famous palindrome "A Man, A Plan, A Canal, Panama" as the title.

The first and last tracks on Andrew Bird's album Noble Beast form a palindrome ("Oh No" and "On Ho!") and the seventh track is a palindrome in itself: "Ouo". He has also mentioned palindromes in earlier music, giving his songs names such as "11:11", "T'N'T", and "Fake Palindromes" (although the last title is not a palindrome itself). He also mentions palindromes in the lyrics of the song "I" and the "I" redux "Imitosis".

"racEcar" by Vitamin Party features a repeating chorus of "A Man, A Plan, A Canal, Panama" (the title itself is palindromic).

"Never Odd or Even", which was to be the title of the first album by Aleka's Attic, the band formed by the late River Phoenix, is a palindrome.[15]

"Neveroddoreven" (or "Never Odd or Even") is the title of an album by Shonlock, released in 2011. This palindrome is stylized on the album's cover as "NEVERODⱭOЯƎVƎИ". This album also contains the song "Never Odd or Even".

"If I Had a Hi-Fi", a 2010 cover album by American alternative rock band Nada Surf, is a palindrome.

Miles Davis and Black Sabbath both had albums called Live Evil. Inversely, Lynch Mob and Diamond Head had albums called Evil Live.

D.R.U.G.S. has two songs that are palindromes on the self-titled debut album, "Mr. Owl Ate My Metal Worm" and "Laminated E.T. Animal".

In 2009, rock band "Dopapod" released an album entitled "I Saw Live Dopapod Evil Was I".

The Asian-American teenage Riot Grrrl band Emily's Sassy Lime's name is palindromic.

In 2012, the American band Liars released an LP called WIXIW.

The German electronic trio To Rococo Rot is also a palindrome.

Dopapod, a palindrome in itself, has a live album titled "I saw live Dopapod evil was I".


Watchmen #5, "Fearful Symmetry", the first page mirrors the last (in terms of frame disposition), with the following pages mirroring each other before the center-spread is (broadly) symmetrical in layout.

"NogegoN", Volume 3 of Les Terres creuses, by Luc et François Schuiten, Les Humanoïdes Associés, (1990) : each frame has its mirror image.


Disney's Phineas and Ferb frequently alludes to palindromes, including the once-mentioned character Professor Ross E. Forp. Danville, the setting locale is also said to have a "Palindrome Road".

In a Time Warp Trio episode, a palindrome is needed, and the characters come up with "Go hang a salami, I'm a lasagna hog".

Long palindromes[edit]

The longest palindromic word in the Oxford English Dictionary is the onomatopoeic tattarrattat, coined by James Joyce in Ulysses (1922) for a knock on the door.[16][17] The Guinness Book of Records gives the title to detartrated, the preterite and past participle of detartrate, a chemical term meaning to remove tartrates. Rotavator, a trademarked name for an agricultural machine, is often listed in dictionaries. The term redivider is used by some writers, but appears to be an invented or derived term—only redivide and redivision appear in the Shorter Oxford Dictionary. Malayalam, an Indian language, is of equal length.

In English, two palindromic novels have been published: Satire: Veritas by David Stephens (1980, 58,795 letters), and Dr Awkward & Olson in Oslo by Lawrence Levine (1986, 31,954 words).[18] What is more well known is the 224 word long poem "Dammit I'm Mad" by Demetri Martin.[19] In French, Oulipo writer Georges Perec's "Grand Palindrome" (1969) is 5,556 letters in length.[20][21] In Hebrew, Noam Dovev wrote a 1,001-word, 3,773 letter palindromic story called, "Name sold, I'd lose man".[22][23]

Biological structures[edit]

Main article: Palindromic sequence
Palindrome of DNA structure
A: Palindrome, B: Loop, C: Stem



It is believed that palindromes frequently are also found in proteins,[24][25] but their role in the protein function is not clearly known. It has recently[26] been suggested that the prevalence existence of palindromes in peptides might be related to the prevalence of low-complexity regions in proteins, as palindromes frequently are associated with low-complexity sequences. Their prevalence might also be related to an alpha helical formation propensity of these sequences,[26] or in formation of proteins/protein complexes.[27]

Computation theory[edit]



It is possible to find the longest palindromic substring of a given input string in linear time.[28][29]


 d_P(w) = \left( { \limsup_{k \rightarrow \infty} \frac{n_{k+1}}{n_k} } \right)^{-1} \ .


A palstar is a composition of palindromic strings.[28]


Semordnilap is a name coined for a word or phrase that spells a different word or phrase backward. "semordnilap" is itself "palindromes" spelled backward. According to logologist Dmitri A. Borgmann,[31] the word was coined by Martin Gardner in Oddities and Curiosities of Words and Literature.[32] Semordnilaps are also known as volvograms,[33] heteropalindromes, semi-palindromes, half-palindromes, reversgrams, mynoretehs, reversible anagrams,[34] word reversals, or anadromes.[35] They have also sometimes been called antigrams,[35] though now, this term usually refers to anagrams with opposing meanings.

These words are very useful in constructing palindromic texts; together, each pair forms a palindrome, and they may be added on either side of a shorter palindrome in order to extend it.

Apart from the invented example of "semordnilap/palindromes" itself, the longest examples are eight letters, such as "stressed" ("desserts") and "dioramas" ("samaroid", resembling a samara). Other shorter examples include "deliver" ("reviled"), Zeus ("Suez"), and "swap" ("paws").

Non-English palindromes[edit]

According to Guinness World Records, the Finnish word saippuakivikauppias (soapstone vendor), a 19-letter word, is claimed to be the world's longest palindromic word in everyday use. A meaningful derivative from it is saippuakalasalakauppias (soapfish bootlegger). An even longer effort is saippuakuppinippukauppias (soap dish wholesale vendor), albeit somewhat contrived in its meaning. The proper name "Otto Nenonen" is often combined with the previous noun(s), making the name-title combination an even longer phrase. Almost equally long is the Estonian word kuulilennuteetunneliluuk (the hatch a bullet flies out of when exiting a tunnel).

The longest palindrome in the Dutch language, according to the Dutch Guinness Book of World Records, is koortsmeetsysteemstrook, which translates into English as strip of a fever measurement system.[36]

See also[edit]



  1. ^ Mathematical Circus, p. 250
  2. ^ "". 2007-01-25. Retrieved 2012-04-23. 
  5. ^ Noting the first exile of Napoleon to Elba
  7. ^ "Professor Peter Hilton". Daily Telegraph (London). 10 November 2010. Retrieved 30 April 2011. 
  10. ^ "". Retrieved 2012-04-23. 
  14. ^ "City of San Diego Public Art website". 2007-10-31. Retrieved 2012-04-23. 
  15. ^ "Rio's Attic - Phoenix Music". Retrieved 2012-04-23. 
  16. ^ James Joyce (1982). Ulysses. Editions Artisan Devereaux. pp. 434–. ISBN 978-1-936694-38-9. "...I was just beginning to yawn with nerves thinking he was trying to make a fool of me when I knew his tattarrattat at the door he must ..." 
  17. ^ O.A. Booty (1 January 2002). Funny Side of English. Pustak Mahal. pp. 203–. ISBN 978-81-223-0799-3. "The longest palindromic word in English has 12 letters: tattarrattat. This word, appearing in the Oxford English Dictionary, was invented by James Joyce and used in his book Ulysses (1922), and is an imitation of the sound of someone ..." 
  18. ^ Eckler, Ross (1996). Making the Alphabet Dance. NY: St. Martin's. p. 36. ISBN 0-333-90334-X. 
  20. ^ Perec, Georges (1973). La Littérature Potentielle, idées. Paris: Gallimard. 
  21. ^ Bellos, David. Georges Perec: A Life in Words. NY: David R. Godine. p. 429. ISBN 0-87923-980-8. 
  22. ^ Dovev, Noam (2013-02-12). "Name sold, I'd lose man". Palindromic blog. 
  23. ^ Arad, Roy Chicky (2013-02-28). "Palindrome - How can you read it?". Haaretz newspaper. 
  24. ^ Ohno S (1990). "Intrinsic evolution of proteins. The role of peptidic palindromes". Riv. Biol. 83 (2-3): 287–91, 405–10. PMID 2128128. 
  25. ^ Giel-Pietraszuk M, Hoffmann M, Dolecka S, Rychlewski J, Barciszewski J (February 2003). "Palindromes in proteins". J. Protein Chem. 22 (2): 109–13. doi:10.1023/A:1023454111924. PMID 12760415. 
  26. ^ a b Sheari A, Kargar M, Katanforoush A, et al. (2008). "A tale of two symmetrical tails: structural and functional characteristics of palindromes in proteins". BMC Bioinformatics 9: 274. doi:10.1186/1471-2105-9-274. PMC 2474621. PMID 18547401. 
  29. ^ Gusfield, Dan (1997), "9.2 Finding all maximal palindromes in linear time", Algorithms on Strings, Trees, and Sequences, Cambridge: Cambridge University Press, pp. 197–199, doi:10.1017/CBO9780511574931, ISBN 0-521-58519-8, MR 1460730 
  30. ^ Adamczewski, Boris; Bugeaud, Yann (2010), "8. Transcendence and diophantine approximation", in Berthé, Valérie; Rigo, Michael, Combinatorics, automata, and number theory, Encyclopedia of Mathematics and its Applications 135, Cambridge: Cambridge University Press, p. 443, ISBN 978-0-521-51597-9, Zbl pre05879512 
  31. ^ Borgmann, Dmitri A. (1965). Language on Vacation. NY: Charles Scribner's Sons. p. 42. 
  32. ^ Bombaugh, C. C. (1961). Gardner, Martin, ed. Oddities and Curiosities of Words and Literature. p. 345. 
  33. ^ "Merriam-Webster's Open Dictionary". 2005-09-26. Retrieved 2012-04-23. 
  34. ^ "AskOxford: What is the word for a word that is another word spelt backwards?". Retrieved 2012-04-23. 
  35. ^ a b "Anagrams FAQ Page - Are there any unusual varieties of anagram?". 2011-03-19. Retrieved 2012-04-23. 
  36. ^ "Wikipedia De vrije encyclopedie". Wikimedia Foundation, Inc. 2013-12-17. Retrieved 2013-12-21. 

External links[edit]