<p><strong>Noun</strong></p><ul><li>A commissioned military officer ranking next below a lieutenant colonel and next above a captain.</li><li>One of superior rank, ability, etc., in a specified class.</li><li>A subject or field of study chosen by a student to represent their principal interest and upon which a large share of their efforts are concentrated: History was my major in college.</li><li>A student engaged in such study.</li><li>A person of full legal age (minor).</li><li>A major interval, chord, scale, etc.</li><li>The major leagues: major league: He coached in the majors as well as in the minors.</li><li>The companies or organizations that lead or control a particular field of activity: the oil majors.</li></ul><p><strong>Adjective</strong></p><ul><li>Greater in size, extent, or importance: the major part of the town.</li><li>Great, as in rank or importance: a major artist.</li><li>A major political issue; a major artist.</li><li>Serious or risky: a major operation.</li><li>Of or relating to the majority: the major opinion.</li><li>Of full legal age.</li><li>(Of an interval) Being between the tonic and the second, third, sixth, or seventh degrees of a major scale: a major sixth, a major third.</li><li>(Of a chord) Having a major third between the root and the note next above it.</li><li>Pertaining to the subject in which a student takes the most courses: Her major field is English history.</li><li>(Initial capital letter) (Of one of two male students in an English public school who have the same surname) Being the elder or higher in standing: Hobbes Major is not of a scientific bent.</li></ul><p><strong>Verb</strong></p><ul><li>(Used without object) To follow a major course of study: He is majoring in physics.</li></ul>