theology vs field of study

theology and field of study both are nouns.

Word	Noun	Adjective	Verb	Adverb
theology	Yes	No	No	No
field of study	Yes	No	No	No

As nouns, field of study is a hypernym of theology; that is, field of study 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
field of study: a branch of knowledge

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

theology (noun)	field of study (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