go hang a salami, i'm a lasagna hog

a palindrome is something that is the same backwards as it is forwards. this can be a number, a sound, a gene sequence, a word, or (as in the title) a phrase.
the word "palindrome" has greek roots, but the greeks themselves called this kind of word or phrase a "crab," referring to the way crabs walk.

without further ado lets get some examples of palindromic words:

• racecar
• kayak
• level
  

and the much more impressive palindromic phrases:

• was it a rat i saw?
• ed is on no side
• sit on a potato pan, otis
• more
  

and some famous palindromes:

• satan, oscillate my metallic sonatas (used as an album title by grunge bad soundgarden)
• a man, a plan: a canal. panama! (referring to the creation of the panama canal)
  
• able was i, ere i saw elba (napoleon's thoughts after being exiled)

 similar to a palindrome is a sequence called a semordnilap, which is itself "palindromes" spelled backwards. this gives a hint as to what a semordnilap is: a word/phrase/sequence that has meaning when presented backwards, though a differet meaning then when presented forwards. I have actually featured one of these on this blog once already without realizing it: "desserts" spelled backwards is "stressed."