theology vs subject area

theology and subject area both are nouns.

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

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

theology: the rational and systematic study of religion and its influences and of the nature of religious truth
subject area: a branch of knowledge

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

theology (noun)	subject area (noun)
the learned profession acquired by specialized courses in religion (usually taught at a college or seminary)	a branch of knowledge
a particular system or school of religious beliefs and teachings
the rational and systematic study of religion and its influences and of the nature of religious truth