A word that reads the same backward as forward, such as “level,” is called a palindrome. The defining feature is symmetry: reversing the sequence produces the same letters in the same order.
The term can describe words, numbers, phrases, or other symbolic sequences. “Radar,” “civic,” “madam,” and “rotor” are English word palindromes. In phrases, punctuation, spaces, and capitalization are often ignored; “A man, a plan, a canal, Panama” is a famous example. Palindromic numbers include 121 and 1331.
English poet and writer Henry Peacham introduced the word palindrome in 1638. It comes from Greek roots meaning “running back again.” The idea is much older: the Sator Square, a famous Latin word square from the Roman era, contains palindromic patterns. A common mix-up is confusing a palindrome with an anagram. An anagram rearranges letters into a different sequence, while a palindrome specifically preserves the sequence when read in reverse.