subject area vs discipline

subject area and discipline both are nouns.

Word	Noun	Adjective	Verb	Adverb
subject area	Yes	No	No	No
discipline	Yes	No	Yes	No

As nouns, subject area and discipline are synonyms defined as:

Other synonyms of subject area include bailiwick, field, field of study, study, subject, subject field.

subject area (noun)	discipline (noun)
a branch of knowledge	training to improve strength or self-control
	the act of disciplining
	the trait of being well behaved
	a branch of knowledge
	a system of rules of conduct or method of practice

subject area (verb)	discipline (verb)
	punish in order to gain control or enforce obedience
	develop (a child's or animal's) behavior by instruction and practice; especially to teach self-control