1) A sub-division of the plenary mandated to negotiate specific issues of the agenda, usually arranged by clusters. Open to all parties. 2) Between meetings, a subsidiary body established by the governing body of an international agreement to provide it with advice on specific issues. These working groups can be open-ended and meet periodically or be time-bound and meet once only. Open to all parties. (Source: Glossary of terms for Negotiators of MEAs, 2007)