What Is a Palindrome?
A palindrome is a word, phrase, number, or other sequence that reads the same backwards as forwards once you ignore spaces, punctuation, and capital letters. The word itself comes from the Greek for "running back again."
Palindrome examples
| Word / Phrase | Cleaned | Length |
|---|---|---|
| racecar | racecar | 7 |
| Madam, I'm Adam | madamimadam | 11 |
| 12321 | 12321 | 5 |
| A man, a plan, a canal: Panama | amanaplanacanalpanama | 21 |
| Never odd or even | neveroddoreven | 14 |
Where the word comes from
The term palindrome comes from the Greek palíndromos — palin ("again") plus dromos ("running") — literally "running back again." It is generally credited to the 17th-century English playwright Ben Jonson.
Types of palindrome
Single words (racecar, level), names (Anna, Otto), whole sentences ("Was it a car or a cat I saw?"), and numbers or dates (12321, 02/02/2020) can all be palindromes. The convention is to compare the letters or digits themselves, not the spaces and punctuation around them.