oncology vs medical specialty

oncology and medical specialty both are nouns.

Word	Noun	Adjective	Verb	Adverb
oncology	Yes	No	No	No
medical specialty	Yes	No	No	No

As nouns, medical specialty is a hypernym of oncology; that is, medical specialty is a word with a broader meaning than oncology:

oncology: the branch of medicine concerned with the study and treatment of tumors
medical specialty: the branches of medical science that deal with nonsurgical techniques

Other hypernyms of oncology include medicine.

oncology (noun)	medical specialty (noun)
the branch of medicine concerned with the study and treatment of tumors	the branches of medical science that deal with nonsurgical techniques