The Collaborative International Dictionary of English v.0.48:

Majority \Ma*jor"i*ty\, n.; pl. Majorities. [F. majorit['e].
   See Major.]
   1. The quality or condition of being major or greater;
      superiority. Specifically:
      (a) The military rank of a major.
      (b) The condition of being of full age, or authorized by
          law to manage one's own affairs.
          [1913 Webster]

   2. The greater number; more than half; as, a majority of
      mankind; a majority of the votes cast.
      [1913 Webster]

   3. [Cf. L. majores.] Ancestors; ancestry. [Obs.]
      [1913 Webster]

   4. The amount or number by which one aggregate exceeds all
      other aggregates with which it is contrasted; especially,
      the number by which the votes for a successful candidate
      exceed those for all other candidates; as, he is elected
      by a majority of five hundred votes. See Plurality.
      [1913 Webster]

   To go over to the majority or To join the majority, to
      die.
      [1913 Webster]

WordNet (r) 3.0 (2006):

majority
    n 1: the property resulting from being or relating to the
         greater in number of two parts; the main part; "the
         majority of his customers prefer it"; "the bulk of the work
         is finished" [syn: majority, bulk] [ant: minority]
    2: (elections) more than half of the votes [syn: majority,
       absolute majority]
    3: the age at which persons are considered competent to manage
       their own affairs [syn: majority, legal age] [ant:
       minority, nonage]

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "majority":
   accomplishment, adulthood, adultness, age of consent, ascendancy,
   best part, better part, body, bulk, deanship, driving age, essence,
   excellence, favor, flower of age, full age, full bloom,
   full growth, fullgrownness, generality, gist, gravamen, greatness,
   grown-upness, incomparability, inimitability, lead, legal age,
   legalis homo, main body, major part, manhood, manlihood, mass,
   mature age, maturity, meat, more than half, most, one-upmanship,
   plurality, precedence, predominance, predomination, preeminence,
   preponderance, preponderancy, prepotence, prepotency, prerogative,
   prestige, prime, prime of life, priority, privilege, right-of-way,
   ripe age, riper years, seniority, skill, substance, success,
   superiority, the greatest number, thrust, toga virilis,
   transcendence, transcendency, virility, virtuosity, womanhood,
   womanlihood, years of discretion



Bouvier's Law Dictionary, Revised 6th Ed (1856):

MAJORITY, persons. The state or condition of a person who has arrived at
full age. He is then said to be a major, in opposition to minor, which is
his condition during infancy.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

MAJORITY, government. The greater number of the voters; though in another
sense, it means the greater number of votes given in which sense it is a
mere plurality. (q.v.)
     2. In every well regulated society, the majority has always claimed and
exercised the right to govern the whole society, in the manner pointed out
by the fundamental laws and the minority are bound, whether they have
assented or not, for the obvious reason that opposite wills cannot prevail
at the same time, in the same society, on the same subject. 1 Tuck. Bl. Com.
App. 168, 172; 9 Dane's Ab. 37 to 43; 1 Story, Const. Sec. 330.
     3. As to the rights of the majority of part owners of vessels, vide 3
Kent, Com. 114 et seq. As to the majority of a church, vide 16 Mass. 488.
     4. In the absence of all stipulations, the general rule in partnerships
is, that each partner has an equal voice, and a majority acting bonafide,
have the right to manage the partnership concerns, and dispose of the
partnership property, notwithstanding the dissent of the minority; but in
every case when the minority have a right to give an opinion, they ought to
be notified. 2 Bouv. Inst. n. 1954.
     5. As to the majorities of companies or corporations, see Angel, Corp.
48, et seq.;  3 M. R. 495. Vide, generally, Rutherf. Inst. 249; 9 Serg. &
Rawle, 99; Bro. Corporation, pl. 63; 15 Vin. Abr. 183, 184; and the article
Authority; Plurality; Quorum.