nephrology vs medical specialty

nephrology and medical specialty both are nouns.

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

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

nephrology: the branch of medicine concerned with the kidney - its development and anatomy and physiology and disorders
medical specialty: the branches of medical science that deal with nonsurgical techniques

Other hypernyms of nephrology include medicine.

nephrology (noun)	medical specialty (noun)
the branch of medicine concerned with the kidney - its development and anatomy and physiology and disorders	the branches of medical science that deal with nonsurgical techniques