excretion vs guano

excretion and guano both are nouns.

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

As nouns, guano is a hyponym of excretion; that is, guano 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
guano: the excrement of sea birds; used as fertilizer

excretion (noun)	guano (noun)
the bodily process of discharging waste matter	the excrement of sea birds; used as fertilizer
waste matter (as urine or sweat but especially feces) discharged from the body