A palindrome is a word or phrase whose sequence of letters is the same when read forward or backward. The word 'palindrome' first appeared in print in the 1638 book, "The Truth of Our Times" by Henry Peacham. The word stems from ancient Greek roots: 'palin' meaning "again", and 'dromos' meaning "way" or "direction".

"Repaper", meaning cover with paper again, is a palindrome, as are these other examples:

- "racecar"

- "madam"

- "kayak"

- "rotavator"

Palindromic phrases can be read forward or backwards (if punctuation is ignored). Examples of palindromic phrases include:

- "Do geese see God?"

- "A man, a plan, a canal, Panama!"

- "Ed, I saw Harpo Marx ram Oprah W. aside."

- "Are we not pure? “No, sir!” Panama’s moody Noriega brags. “It is garbage!” Irony dooms a man—a prisoner up to new era."

The photo shows the oldest known palindromic phrase, the 'Sator Square'. The stone was discovered in the town of Herculaneum which, like the city of Pompeii, was inundated by lava from the eruption of Vesuvius in 79 AD.

The Latin palindromic phrase on the stone can be read in four different directions: horizontally or vertically from either top left to bottom right or bottom right to top left. The Latin phrase "Sator Arepo Tenet Opera Rotas" translates to English as "The sower Arepo holds with effort the wheels".

Numbers and dates can also be palindromes. The first palindromic date of the year 2020 is on February 2nd: 02/02/2020.

More Info: en.wikipedia.org