General knowledge · Words & language

Palindromes

Term coined 1638

Wordplay — sequences that read the same both ways

Words, phrases or numbers that read identically forwards and backwards, from the Greek palin ("again") and dromos ("way, running"). The English term was coined by the poet Henry Peacham in 1638, though the oldest surviving examples are ancient: the Latin Sator Square scratched on a wall at Pompeii, and a Greek line found on Byzantine fonts. They turn up far beyond wordplay — in the crab canons of music, in DNA sequences that read the same on both strands, and in formal language theory, where the set of all of them is context-free but not regular.

How to spot them

▸From the Greek for 'running back again'; the term was coined in 1638
▸Sator arepo tenet opera rotas — a word square found at Pompeii
▸'Able was I ere I saw Elba', wrongly credited to Napoleon
▸A word reversed to make a different word is a semordnilap — itself an example

Key facts

'Sator arepo tenet opera rotas', scratched as graffiti at Pompeii (1st century AD)

A five-by-five word square that reads the same four ways; the sower Arepo holds the wheels

'Able was I ere I saw Elba', coined in 1848 and long misattributed to an exiled emperor (1848)

Its true author signed himself only 'J.T.R.'

Leigh Mercer's 1948 tribute to a waterway: 'A man, a plan, a canal — Panama' (1948)

Mercer (1893–1977) is remembered almost entirely for this one line

The Finnish saippuakivikauppias — a soapstone vendor, nineteen letters long

Guinness World Records calls it the longest such word in everyday use

Joyce coined 'tattarrattat' in Ulysses for a knock at the door (1922)

At twelve letters it is the longest example in the Oxford English Dictionary

The Latin riddle 'In girum imus nocte et consumimur igni', describing moths

'We go in a circle at night and are consumed by fire' — probably medieval, not ancient

In music, the crab canon; in biology, the sequences restriction enzymes cut

Both read the same in reverse, one in notes and one in base pairs

Quick-fire facts

•The word was introduced by the English poet and writer Henry Peacham in 1638
•It comes from Greek palin, 'again', and dromos, 'way' or 'running'
•The Sator Square, found at Pompeii, is both a word square and a sentence that reads the same backwards
•John Taylor's 'Lewd did I live, & evil I did dwel' (1614) is usually called the first English example
•'Madam, I'm Adam' dates from 1861 and 'Never odd or even' from 1930
•Guinness World Records gives the longest English single-word example as the eleven-letter 'detartrated'
•Common English examples include level, rotor, kayak, civic, radar, deified and racecar
•22 February 2022 (22/02/2022) was a widely noted palindromic date, and a Tuesday
•A 'semordnilap' is a word that spells a different word backwards, such as stressed and desserts
•In automata theory the set of all palindromes over an alphabet is a context-free but not a regular language

Drill it — 8 cards

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Sources

David Crystal — Language Play
Oxford University Press — Oxford English Dictionary Consulted for tattarrattat and the coinage date of 'palindrome'; subscription-only, cited without URL