thyrotoxicosis vs gland disease

thyrotoxicosis and gland disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
thyrotoxicosis	Yes	No	No	No
gland disease	Yes	No	No	No

As nouns, gland disease is a hypernym of thyrotoxicosis; that is, gland disease is a word with a broader meaning than thyrotoxicosis:

thyrotoxicosis: an overactive thyroid gland; pathologically excessive production of thyroid hormones or the condition resulting from excessive production of thyroid hormones
gland disease: a disorder of the glands of the body

Other hypernyms of thyrotoxicosis include adenosis, glandular disease, glandular disorder.

thyrotoxicosis (noun)	gland disease (noun)
an overactive thyroid gland; pathologically excessive production of thyroid hormones or the condition resulting from excessive production of thyroid hormones	a disorder of the glands of the body