megavitamin therapy vs therapy

megavitamin therapy and therapy both are nouns.

Word	Noun	Adjective	Verb	Adverb
megavitamin therapy	Yes	No	No	No
therapy	Yes	No	No	No

As nouns, therapy is a hypernym of megavitamin therapy; that is, therapy is a word with a broader meaning than megavitamin therapy:

megavitamin therapy: therapy based on a theory that taking very large doses of vitamins will prevent or cure physical or psychological disorders
therapy: (medicine) the act of caring for someone (as by medication or remedial training etc.)

Other hypernyms of megavitamin therapy include treatment.

megavitamin therapy (noun)	therapy (noun)
therapy based on a theory that taking very large doses of vitamins will prevent or cure physical or psychological disorders	(medicine) the act of caring for someone (as by medication or remedial training etc.)