Other forms: members
A member is somebody who belongs to a club, a group or an organisation. A club member, a member of staff, members only.
The pattern is a member of something, and that of is not optional. In Britain, an MP is a Member of Parliament and the capital letters matter. A member state is a country belonging to an organisation such as the EU or the UN. The noun membership means both the state of belonging and all the members together: membership has fallen. Note the older sense meaning a limb, which survives in the phrase members of the body and in dismember.
1nounmemberSomebody who belongs to a group or organisation.
“She's a member of the local tennis club.”
2nouncountryA country belonging to an international organisation.
“All twenty-seven member states have to agree.”
3nounsetOne of a set or class.
“It is the smallest member of the family.”
Too few real examples of this word to estimate which sense is commonest.
member is somebody who belongs.
Latin membrum meant a limb or a part of the body. A member of a group was originally a limb of it, and the metaphor of an organisation as a body is old enough that nobody notices it — which is also where corporation comes from, corpus being a body.
Proto-Indo-European
*mḗms — flesh
Proto-Italic
*memzrom
Latin
membrum — limb, body part
Old French
membre
Middle English
membre
English, today
member
From Middle English membre, from Old French membre, from Latin membrum (“limb, body part”), from Proto-Italic memzrom, from Proto-Indo-European mḗms (“flesh”). Akin to Gothic 𐌼𐌹𐌼𐌶 (“meat, flesh”), gme-cgo menus. Coexists with native limb, from lim (“limb, joint, main branch”). Mostly lith, from liþ (“limb, member, join, tip”), which still survives in British dialect.
Etymology from Wiktionary, CC BY-SA