Cluster
From AFSWiki
A cluster generally refers to a group of 3 or more Sponsored Program students in a relatively small geographical area. Sponsored Program students are required to participate in a number of "enrichment activities" intended to be educational (and fun) dealing with the general topics of "Volunteerism"; "Cultural Diversity"; or "Government."
Cluster Coordinator
A cluster coordinator is a volunteer who plans, arranges, and co-ordinates enrichment activities for a sponsored programs cluster and documents the activity so the sponsor (usually the U.S. government) could if it chose determine that the activities met the program requirements.
A cluster coordinator is also known as a Sponsored Programs Coordinator.
See the Cluster Coordinator Manual here.