arts vs subject area

arts and subject area both are nouns.

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

As nouns, subject area is a hypernym of arts; that is, subject area is a word with a broader meaning than arts:

arts: studies intended to provide general knowledge and intellectual skills (rather than occupational or professional skills)
subject area: a branch of knowledge

Other hypernyms of arts include bailiwick, discipline, field, field of study, study, subject, subject field.

arts (noun)	subject area (noun)
studies intended to provide general knowledge and intellectual skills (rather than occupational or professional skills)	a branch of knowledge