Source : Webster's Revised Unabridged Dictionary (1913)

Murphy \Mur"phy\, n.
   A potato. [Humorous] --Thackeray.

Source : WordNet®

murphy
     n : an edible tuber native to South America; a staple food of
         Ireland [syn: {potato}, {white potato}, {Irish potato}, {spud},
          {tater}]