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"

Moby Thesaurus II by Grady Ward, 1.0:

180 Moby Thesaurus words for "leadership":
   acme, administration, aedileship, archbishopric, archiepiscopacy,
   archiepiscopate, aristocracy, ascendancy, authority, authorization,
   be-all and end-all, bishopric, blue ribbon, captainship,
   chairmanship, championship, chancellery, chancellorate,
   chancellorship, charisma, charm, chiefery, chiefry, chieftaincy,
   chieftainry, chieftainship, clout, command, consequence, consulate,
   consulship, control, convenership, credit, custody, deanery,
   dictatorship, dictature, direction, directorate, directorship,
   dominance, domination, dominion, effect, effectiveness, eminence,
   emirate, enchantment, episcopacy, esteem, favor, first place,
   first prize, force, foremanship, generalship, good feeling,
   governorship, guardianship, guidance, headship, hegemony, height,
   hierarchy, highest, hold, imperium, importance, incidental power,
   influence, influentiality, initiative, insinuation, intendancy,
   jurisdiction, kingship, leverage, lordship, magistracy,
   magistrateship, magistrature, magnetism, management, managership,
   masterdom, mastership, mastery, maximum, mayoralty, mayorship,
   metropolitanate, metropolitanship, moment, most, ne plus ultra,
   new high, nobility, operation, overseership, palms, papacy,
   paramountcy, pashadom, pashalic, patriarchate, patriarchy,
   personality, persuasion, pontificality, pontificate, popedom,
   popehood, popeship, potency, power, predominance, prefectship,
   prefecture, premiership, preponderance, presidency, presidentship,
   pressure, prestige, primacy, prime-ministership, prime-ministry,
   princedom, princeship, principality, proconsulate, proconsulship,
   proctorship, protectorate, protectorship, provostry, provostship,
   purchase, record, rectorate, rectorship, regency, regentship,
   regulation, reign, repute, rule, ruling class, running, say,
   seigniory, seneschalship, seneschalsy, sheikhdom, sheriffalty,
   sheriffcy, sheriffdom, shrievalty, sovereignty, stewardship,
   suasion, subtle influence, suggestion, superintendence,
   superintendency, supervision, supervisorship, supremacy,
   suzerainship, suzerainty, sway, top spot, tribunate, upper hand,
   vizierate, viziership, weight, whip hand, zenith