hypovolaemia vs blood disorder

hypovolaemia and blood disorder both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypovolaemia	Yes	No	No	No
blood disorder	Yes	No	No	No

As nouns, blood disorder is a hypernym of hypovolaemia; that is, blood disorder is a word with a broader meaning than hypovolaemia:

hypovolaemia: a blood disorder consisting of a decrease in the volume of circulating blood
blood disorder: a disease or disorder of the blood

Other hypernyms of hypovolaemia include blood disease.

hypovolaemia (noun)	blood disorder (noun)
a blood disorder consisting of a decrease in the volume of circulating blood	a disease or disorder of the blood