The Collaborative International Dictionary of English v.0.48:

Leadership \Lead"er*ship\, n.
   1. The office, position or function of a leader; as, Gingrich
      held the House leadership for six years.
      [1913 Webster]

   2. The quality of character and personality giving a person
      the ability to gain the confidence of and lead others; as,
      Washington's leadership was indispensible to success of
      the American Revolution.
      [PJC]

   3. The people who serve as leaders of a group; as, the party
      leadership was in disarray after the election.
      [PJC]

WordNet (r) 3.0 (2006):

leadership
    n 1: the activity of leading; "his leadership inspired the team"
         [syn: leadership, leading]
    2: the body of people who lead a group; "the national leadership
       adopted his plan" [syn: leadership, leaders]
    3: the status of a leader; "they challenged his leadership of
       the union"
    4: the ability to lead; "he believed that leadership can be
       taught"