melaena vs ordure

melaena and ordure both are nouns.

Word	Noun	Adjective	Verb	Adverb
melaena	Yes	No	No	No
ordure	Yes	No	No	No

As nouns, ordure is a hypernym of melaena; that is, ordure is a word with a broader meaning than melaena:

melaena: abnormally dark tarry feces containing blood (usually from gastrointestinal bleeding)
ordure: solid excretory product evacuated from the bowels

Other hypernyms of melaena include BM, dejection, faecal matter, faeces, fecal matter, feces, stool.

melaena (noun)	ordure (noun)
abnormally dark tarry feces containing blood (usually from gastrointestinal bleeding)	solid excretory product evacuated from the bowels