Item

Any bit of data that is seen as a a monolithic chunk. For example in the SKOS package, a skos:ConceptScheme is considered to be an Item, and skos:Collection and skos:Concept inside it are only nodes of the item, not items themselves. How items come do be are defined at the Collection level thanks to construct queries. So conceptually, an item can be as simple as a single node (a single skos:Concept could be configured to be an item) or as complex as a whole graph.