hygienics vs medical specialty

hygienics and medical specialty both are nouns.

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

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

hygienics: the science concerned with the prevention of illness and maintenance of health
medical specialty: the branches of medical science that deal with nonsurgical techniques

Other hypernyms of hygienics include medicine.

hygienics (noun)	medical specialty (noun)
the science concerned with the prevention of illness and maintenance of health	the branches of medical science that deal with nonsurgical techniques