council member; conference participant
Refers to a person who is a member of a formal council, committee, or conference. Often used in organizational or governmental contexts.
He participated as a member of the international council.
The council members hold a meeting every month.
委員 is a general term for a committee member, while 協議会員 specifically refers to a member of a council or conference focused on discussion and deliberation.
会員 is a broader term for any member of an organization or club, whereas 協議会員 is limited to members of a formal council or conference.
Compound of 協議 (discussion, conference) + 会員 (member). The exact historical derivation is uncertain, but the word follows a standard pattern for naming members of formal bodies.