One of the MAP terms
See holon in the Glossary, where it says
Every object in the MAP — whether it’s a piece of content, an Agent, a relationship, a service, or a visual element — is encoded as a self-describing, active Holon or HolonRelationship.
aSimonG: This is a tricky term, primarily because “holon” is not a term that is readily understood by a general reader. Maybe, for reader comprehensibility within the MAP, we may just think of a holon as an “entity”, “object” or “thing”; that is, excluding relationships.