Major

1. A commissioned rank in the U.S. Army, Air Force, or Marine Corps that is above captain and below lieutenant colonel.
2. A similar rank in another military or paramilitary organization. The British major told us of his actions in the war.
3.One who holds this rank. The major reviewed the troops.
4. Greater than others in importance or rank. He is one of the major artist of his day.
5. Great in scope or effect. It was a major improvement to improve efficiency.
6. Of or relation to the field of academic study in which the student specializes. Her major was French history.