plenary
adj.describing a meeting or session where everyone is expected to attend, rather than just a small group. It is often used for the main parts of a big conference.
adj.relating to a session or assembly attended by all participants or members of a body. Often used to distinguish full-group meetings from smaller breakout sessions or committees.
“The conference starts with a plenary session for all guests.”
“After the morning workshops, the delegates gathered in the main hall for the final plenary discussion.”
“The committee's recommendations must be ratified during the plenary assembly before they can be formally adopted into the organization's bylaws.”
Typically used attributively before nouns like 'session', 'meeting', or 'assembly'.
“He said he told Siluanov during a plenary session that Moscow had to end the war and “that we clearly support Ukraine”.”
“He will appear on September 3rd in an extraordinary plenary session, although Sánchez had proposed appearing on the 9th.”
From Middle English plenarie, plenarye, from Late Latin plēnārius, from Latin plēnus (“full”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.