caisson disease vs sickness

caisson disease and sickness both are nouns.

Word	Noun	Adjective	Verb	Adverb
caisson disease	Yes	No	No	No
sickness	Yes	No	No	No

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

caisson disease: pain resulting from rapid change in pressure
sickness: impairment of normal physiological function affecting part or all of an organism

Other hypernyms of caisson disease include illness, malady, unwellness.

caisson disease (noun)	sickness (noun)
pain resulting from rapid change in pressure	impairment of normal physiological function affecting part or all of an organism
	the state that precedes vomiting
	defectiveness or unsoundness