haematochezia vs defecation

haematochezia and defecation both are nouns.

Word	Noun	Adjective	Verb	Adverb
haematochezia	Yes	No	No	No
defecation	Yes	No	No	No

As nouns, defecation is a hypernym of haematochezia; that is, defecation is a word with a broader meaning than haematochezia:

haematochezia: passage of stools containing blood (as from diverticulosis or colon cancer or peptic ulcer)
defecation: the elimination of fecal waste through the anus

Other hypernyms of haematochezia include laxation, shitting.

haematochezia (noun)	defecation (noun)
passage of stools containing blood (as from diverticulosis or colon cancer or peptic ulcer)	the elimination of fecal waste through the anus