n the most important league in any sport (especially baseball)
n a commissioned military officer in the United States Army or Air Force or Marines; below lieutenant colonel and above captain
n British statesman who was prime minister from 1990 until 1997 (born in 1943)
n a university student who is studying a particular field as the principal subject
n the principal field of study of a student at a university
v have as one's principal field of study
