Source : Webster's Revised Unabridged Dictionary (1913)

Palindrome \Pal"in*drome\, n. [Gr. ? running back again; ? again
   + ? to run: cf. F. palindrome.]
   A word, verse, or sentence, that is the same when read
   backward or forward; as, madam; Hannah; or Lewd did I live, &
   evil I did dwel.

Source : WordNet®

palindrome
     n : a word or phrase that reads the same backward as forward