member vs erection

member and erection both are nouns.

Word	Noun	Adjective	Verb	Adverb
member	Yes	No	No	No
erection	Yes	No	No	No

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

Other hyponyms of member include cock, dick, pecker, prick, putz, shaft, tool, micropenis, microphallus, hard-on.

member (noun)	erection (noun)
an external body part that projects from the body	the act of building or putting up
the male sex organ	a structure that has been erected
an organization that is a member of another organization (especially a state that belongs to a group of nations)	an erect penis
one of the persons who compose a social group (especially individuals who have joined and participate in a group organization)
anything that belongs to a set or class