major

1 major /ˈmeɪʤɚ/ adjective
1 major
/ˈmeɪʤɚ/
adjective
Britannica Dictionary definition of MAJOR
1 
a  : very important
b  always used before a noun : large in number, amount, or extent
2 
: very serious or bad
3 
music
a  of a scale : having semitones between the third and fourth and the seventh and eighth notes
2 major /ˈmeɪʤɚ/ noun
plural majors
2 major
/ˈmeɪʤɚ/
noun
plural majors
Britannica Dictionary definition of MAJOR
[count]
1 
: a military officer in the army, air force, or marines who ranks above a captain — see also sergeant major
2 
US
a  : the main subject studied by a college or university student
— compare 2minor 2
b  : a student who has a specified main subject of study

the majors

US, informal
: the major leagues of baseball
3 major /ˈmeɪʤɚ/ verb
majors; majored; majoring
3 major
/ˈmeɪʤɚ/
verb
majors; majored; majoring
Britannica Dictionary definition of MAJOR

major in

[phrasal verb]
major in (something) US, of a college or university student
: to have (a specified subject) as your main subject of study

major on

[phrasal verb]
major on (something) British
: to pay special attention to (something)