The phrase "an opening plenary" is correct and usable in written English.
It can be used to refer to the first session or meeting of a conference or event where all participants gather to discuss key topics.
Example: "The conference will begin with an opening plenary that sets the stage for the discussions to follow."
Alternatives: "a kickoff session" or "an inaugural meeting".
After a two-hour opening plenary session on Friday morning largely given over to summarizing known positions, the talks broke at about noon for Friday prayers and lunch, and did not resume again until 4 p.m.
Although they were promised a slot at the opening plenary session, this was later cancelled.
This past weekend, Dawson -- who is set to play labor leader Dolores Huerta in the upcoming Cesar Chavez biopic -- addressed a packed conference hall at the University of Southern California during the opening plenary of the Voto Latino Power Summit, an organization dedicated to engaging Latino youth voters and leaders, of which she is a co-founder and chairwoman.
The next week our team arrived at the U.N. headquarters in New York with high anticipation of a successful workshop right after the opening plenary session of the conference.
As it happens, the official opening plenary is still delayed two-and-a-half hours.
The conference program was composed of an opening session, plenary sessions, and workgroup meetings and presentations.
A rundown of the key moments from the opening plenary, including Skoll's ambition to create the most important media company in the world, can be found here.
Still, speakers at the conference's opening plenary session — which began with a video appeal from children across the world to save them from what looked like an apocalyptic future of deserts and rising seas — were clearly aiming to spur negotiators forward.
The UN deputy secretary-general, Jan Eliasson, mentioned "open defecation" five times during his speech at the opening plenary of World Water Week in Stockholm on 2 September.
"The damage it causes to a child's development is irreversible," UNICEF Executive Director Anthony Lake said, addressing the opening plenary session of the 126th Inter-Parliamentary Union (IPU) Assembly in Kampala, Uganda.
