noun (n)

• game equipment consisting of one of several small six-pointed metal pieces that are picked up while bouncing a ball in the game of jacks(noun.artifact)

  Synonym:
  jack
  

  source: wordnet30
• a game in which jackstones are thrown and picked up in various groups between bounces of a small rubber ball(noun.act)

  Synonym:
  jacks, knucklebones
  

  source: wordnet30