Definition of: major

(mā′jər) adjective
1. Greater in number, quantity, or extent.
2. Greater in dignity or importance; of primary consideration; principal; leading.
3. Music a Designating a chord or interval greater by a half–step than the preceding minor, b Containing a major third, sixth, and seventh. See INTERVAL.
4. Logic Designating the first premise of a syllogism, or the premise containing the first proposition.
5. Law Being of legal age.
—noun
1. An officer in the U. S. Army, Air Force, or Marine Corps ranking next above a captain and next below a lieutenant colonel.
2. Law One who is of legal age.
3. Music A major key, chord, or interval.
4. U.S. The specialized course of study in a definite field which a college or university student follows to obtain his degree.
5. U.S. A student who follows a (specified) course of study: an English major.
—v.i. To pursue a definite field of study: with in: to major in history. [<L, compar. of magnus great. Doublet of MAYOR.]