A word spelled the same forwards and backwards, like “racecar,” is called a palindrome. The letters match when read from left to right and from right to left, usually ignoring spaces, punctuation, and capitalization when phrases are involved.
Other familiar English word palindromes include “level,” “radar,” “civic,” “kayak,” “madam,” and “refer.” Palindromes are not limited to words: numbers such as 1221 and phrases such as “A man, a plan, a canal, Panama” can also qualify under the appropriate rules.
The term comes from Greek roots meaning “running back again.” English poet and writer Henry Peacham introduced the word into English in 1638, although the underlying idea is much older. The ancient Sator Square is a famous early example of a word-square palindrome. A common mix-up is “anagram,” which means rearranging letters into another order; an anagram does not need to read identically in reverse. “Isogram” instead describes a word with no repeated letters.