of a college or university student, "focus (one's) studies," 1910, American English, from major (n.) in sense of "subject of specialization" (by 1890). Related: Majored; majoring. Earlier as a verb, in Scottish, "to prance about, or walk backwards and forwards with a military air and step" [Jamieson, 1825] a sense derived from the military major.
military rank above captain and below lieutenant colonel, 1640s, from French major, short for sergent-major, originally a higher rank than at present, from Medieval Latin major "chief officer, magnate, superior person," from Latin maior "an elder, adult," noun use of the adjective (see major (adj.)).
His chief duties consist in superintending the exercises of his regiment or battalion, and in putting in execution the commands of his superior officer. His ordinary position in the line is behind the left wing. [Century Dictionary, 1897]
The musical sense is attested by 1797.
c. 1300, majour, "greater, more important or effective, leading, principal," from Latin maior (earlier *magios), irregular comparative of magnus "large, great" (from PIE root *meg- "great"). From 1590s as "greater in quantity, number, or extent." Used in music (of modes, scales, or chords) since 1690s, on notion of an interval a half-tone "greater" than the minor; of modern modes, "characterized by the use of major tonality throughout," by 1811. Major league, in baseball, is attested by 1892.
also majordomo, "man employed to superintend a household, especially that of a sovereign or other dignitary," 1580s, via Italian maggiordomo or Spanish mayordomo, from Medieval Latin major domus "chief of the household," also "mayor of the palace" under the Merovingians, from Latin maior "greater" (see major (adj.)) + genitive of domus "house" (from PIE root *dem- "house, household").
1704, of a letter, "capital;" 1738 as a noun, "a capital letter," from French majuscule (16c.), from Latin maiuscula (littera), fem. of maiusculus "somewhat larger, somewhat greater," diminutive of maior (see major (adj.)).
1550s, "state or condition of being greater, superiority"(a sense now obsolete), from French majorité (16c.), from Medieval Latin majoritatem (nominative majoritas) "majority," from Latin maior "greater" (see major (adj.)).
Sense of "state of being of full age, age at which the law permits a young person to manage his own affairs," is attested from 1560s. The meaning "greater number or part, more than half of the whole" (of votes, etc.) is by 1690s; that of "the excess of one of two groups of enumerated votes over the other" is by 1743. The majority "the dead" recorded from 1719; hence euphemistic verbal phrase join the majority.
It forms all or part of: acromegaly; Almagest; Charlemagne; maestro; magisterial; magistral; magistrate; Magna Carta; magnate; magnitude; magnum; magnanimity; magnanimous; magni-; Magnificat; magnificence; magnificent; magnify; magniloquence; magniloquent; Magnus; maharajah; maharishi; mahatma; Mahayana; Maia; majesty; major; major-domo; majority; majuscule; master; maxim; maximum; may (v.2) "to take part in May Day festivities;" May; mayor; mega-; megalo-; mickle; Mister; mistral; mistress; much; omega.
It is the hypothetical source of/evidence for its existence is provided by: Armenian mets "great;" Sanskrit mahat- "great, mazah- "greatness;" Avestan mazant- "great;" Hittite mekkish "great, large;" Greek megas "great, large;" Latin magnus "great, large, much, abundant," major "greater," maximus "greatest;" Middle Irish mag, maignech "great, large;" Middle Welsh meith "long, great."
"female baton-twirler," 1939, short for drum-majorette (1938), fem. of drum-major (1590s; see drum (n.)).
The perfect majorette is a pert, shapely, smiling extrovert, who loves big, noisy crowds and knows how to make those crowds love her. [Life magazine, Oct. 10, 1938]
(The article notes that the activity "has been going on for about six years now").