excretion vs BM

excretion and BM both are nouns.

Word	Noun	Adjective	Verb	Adverb
excretion	Yes	No	No	No
BM	Yes	No	No	No

As nouns, BM is a hyponym of excretion; that is, BM is a word with a more specific, narrower meaning than excretion:

excretion: waste matter (as urine or sweat but especially feces) discharged from the body
BM: solid excretory product evacuated from the bowels

excretion (noun)	BM (noun)
the bodily process of discharging waste matter	solid excretory product evacuated from the bowels
waste matter (as urine or sweat but especially feces) discharged from the body