The Collaborative International Dictionary of English v.0.48:

football \foot"ball`\, n.
   An inflated ball to be kicked in sport, usually made in India
   rubber, or a bladder incased in Leather. --Waller.
   [1913 Webster]

   Note: The American football is an oblate spheroid, with
         pointed ends. In other countries, the football is the
         same as a soccer ball. The games played with the two
         different balls are different. In the United States,
         the game played with a soccer ball is called soccer.
         [PJC]

   2. The game played with a football[1], by two opposing teams
      of players moving the ball between goals at opposite ends
      of a rectangular playing field. Outside the United States
      football refers to soccer, and in England, also to rugby,
      but in the United States the shape of the ball and the
      rules of the game are different. --Arbuthnot.
      [1913 Webster +PJC]

   3. Soccer or rugby. [Brit.]
      [PJC]

   4. [fig.] Something which is treated in a rough manner,
      usually as part of a dispute; as, a political football.
      [PJC]

WordNet (r) 3.0 (2006):

football
    n 1: any of various games played with a ball (round or oval) in
         which two teams try to kick or carry or propel the ball
         into each other's goal [syn: football, football game]
    2: the inflated oblong ball used in playing American football