erectile organ vs penis

erectile organ and penis both are nouns.

Word	Noun	Adjective	Verb	Adverb
erectile organ	Yes	No	No	No
penis	Yes	No	No	No

As nouns, penis is a hyponym of erectile organ; that is, penis is a word with a more specific, narrower meaning than erectile organ:

Other hyponyms of erectile organ include button, clit, clitoris, member, phallus.

erectile organ (noun)	penis (noun)
an organ containing erectile tissue	the male sex organ