The Collaborative International Dictionary of English v.0.48:

Major \Ma"jor\, n. [F. major. See Major, a.]
   1. (Mil.) An officer next in rank above a captain and next
      below a lieutenant colonel; the lowest field officer.
      [1913 Webster]

   2. (Law) A person of full age.
      [1913 Webster]

   3. (Logic) That premise which contains the major term. It its
      the first proposition of a regular syllogism; as: No
      unholy person is qualified for happiness in heaven [the
      major]. Every man in his natural state is unholy [minor].
      Therefore, no man in his natural state is qualified for
      happiness in heaven [conclusion or inference].
      [1913 Webster]

   Note: In hypothetical syllogisms, the hypothetical premise is
         called the major.
         [1913 Webster]

   4. [LL. See Major.] A mayor. [Obs.] --Bacon.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Major \Ma"jor\, [L. major, compar. of magnus great: cf. F.
   majeur. Cf. Master, Mayor, Magnitude, More, a.]
   1. Greater in number, quantity, or extent; as, the major part
      of the assembly; the major part of the revenue; the major
      part of the territory.
      [1913 Webster]

   2. Of greater dignity; more important. --Shak.
      [1913 Webster]

   3. Of full legal age; adult. [Obs.]
      [1913 Webster]

   4. (Mus.) Greater by a semitone, either in interval or in
      difference of pitch from another tone.
      [1913 Webster]

   Major key (Mus.), a key in which one and two, two and
      three, four and five, five and six and seven, make major
      seconds, and three and four, and seven and eight, make
      minor seconds.

   Major offense (Law), an offense of a greater degree which
      contains a lesser offense, as murder and robbery include
      assault.

   Major scale (Mus.), the natural diatonic scale, which has
      semitones between the third and fourth, and seventh and
      fourth, and seventh and eighth degrees; the scale of the
      major mode, of which the third is major. See Scale, and
      Diatonic.

   Major second (Mus.), a second between whose tones is a
      difference in pitch of a step.

   Major sixth (Mus.), a sixth of four steps and a half step.
      In major keys the third and sixth from the key tone are
      major. Major keys and intervals, as distinguished from
      minors, are more cheerful.

   Major third (Mus.), a third of two steps.
      [1913 Webster]

WordNet (r) 3.0 (2006):

major
    adj 1: of greater importance or stature or rank; "a major
           artist"; "a major role"; "major highways" [ant: minor]
    2: greater in scope or effect; "a major contribution"; "a major
       improvement"; "a major break with tradition"; "a major
       misunderstanding" [ant: minor]
    3: greater in number or size or amount; "a major portion (a
       majority) of the population"; "Ursa Major"; "a major portion
       of the winnings" [ant: minor]
    4: of the field of academic study in which one concentrates or
       specializes; "his major field was mathematics" [ant: minor]
    5: of a scale or mode; "major scales"; "the key of D major"
       [ant: minor]
    6: of greater seriousness or danger; "a major earthquake"; "a
       major hurricane"; "a major illness" [ant: minor]
    7: of full legal age [ant: minor, nonaged, underage]
    8: of the elder of two boys with the same family name; "Jones
       major"
    n 1: a commissioned military officer in the United States Army
         or Air Force or Marines; below lieutenant colonel and above
         captain
    2: British statesman who was prime minister from 1990 until 1997
       (born in 1943) [syn: Major, John Major, John R. Major,
       John Roy Major]
    3: a university student who is studying a particular field as
       the principal subject; "she is a linguistics major"
    4: the principal field of study of a student at a university;
       "her major is linguistics"
    v 1: have as one's principal field of study; "She is majoring in
         linguistics"

Moby Thesaurus II by Grady Ward, 1.0:

197 Moby Thesaurus words for "major":
   ADC, CO, OD, a cut above, above, academic specialty, adult, ahead,
   aide, aide-de-camp, area, ascendant, better, big, big-league,
   big-name, big-time, bigger, biggest, bigwig, bigwigged, brigadier,
   brigadier general, capital, capping, captain, chicken colonel,
   chief, chief of staff, chosen, classical education, cock, colonel,
   commandant, commander, commander in chief, commanding officer,
   commissioned officer, company officer, consequential, considerable,
   core curriculum, course, course of study, critical, crucial,
   curriculum, dangerous, discipline, distinguished, dominant,
   dominating, double-barreled, earthshaking, eclipsing, elder,
   eldest, elective, eminent, exceeding, excellent, excelling, exec,
   executive officer, extensive, fell, field, field marshal,
   field officer, finer, first lieutenant, first-born, firstling,
   five-star general, foremost, former, four-star general, general,
   general education, general officer, general studies, generalissimo,
   grand, grave, great, greater, grievous, grown man, grownup,
   heavyweight, hefty, high-powered, higher, humanities, important,
   in ascendancy, in the ascendant, jemadar, junior officer, key,
   key signature, keynote, large, large-scale, larger, legalis homo,
   liberal arts, lieutenant, lieutenant colonel, lieutenant general,
   main, major general, major key, man, marechal, marked, marshal,
   material, mature man, mediant, minor, momentous, name, no chicken,
   notable, noteworthy, of choice, officer, older, oldest, one up on,
   one-star general, orderly officer, outstanding, over, paramount,
   pedal point, predominant, preeminent, primary, prime,
   primogenitary, principal, proseminar, quadrivium, rare,
   refresher course, risaldar, rivaling, scientific education,
   self-important, seminar, senior, senior officer, serious,
   shavetail, significant, sirdar, sizable, specialty, staff officer,
   star, stellar, study, subahdar, subaltern, subdiscipline,
   subdominant, subject, sublieutenant, submediant, substantial,
   subtonic, super, superior, supertonic, surpassing,
   technical education, the Old Man, the brass, three-star general,
   tonality, tonic, tonic key, top brass, topping, transcendent,
   transcendental, transcending, trivium, two-star general, ugly,
   upper, vital, woman, world-shaking, worst



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

MAJOR, persons. One who has attained his full age, and has acquired all his
civil rights; one who is no longer a minor; an adult.



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

MAJOR. Military language. The lowest of the staff officers; a degree higher
than captain.



U.S. Gazetteer Counties (2000):

Major -- U.S. County in Oklahoma
   Population (2000):    7545
   Housing Units (2000): 3540
   Land area (2000):     956.759846 sq. miles (2477.996521 sq. km)
   Water area (2000):    1.105637 sq. miles (2.863587 sq. km)
   Total area (2000):    957.865483 sq. miles (2480.860108 sq. km)
   Located within:       Oklahoma (OK), FIPS 40
   Location:             36.313820 N, 98.448638 W
   Headwords:
    Major
    Major, OK
    Major County
    Major County, OK