plenary /ˈpliːnəɹi/adjective 2noun 2forms 3 adjective2 •Fully attended by a plenum; for everyone's attendance. •Complete; full; entire; absolute.The method of treating a subject should be plenary or full. — 1725 noun2 •A plenary session.After lunch, we will all be in the main auditorium listening to the plenary. •Part of a lesson, usually at or towards the end, designed to review or evaluate the learning that has taken place.Alternatively, the plenary may be used as preparation for the next lesson, and it might support the children to discuss some vocabulary with the TA to help them prepare. — 2004 formsplenaries · more plenary · most plenary