A collection of zero or more things.

Membership within Containers is indicated through the use of rdf:_$ properties, where $ is a positive (i·e nonzero) integer with no leading zeroes. These properties are all considered subproperties of , although there are no normative requirements on processors recognizing this fact. There is no requirement that membership properties be dense; i·e just because a Collection has values for and does not imply it has a value for .

Containers are allowed to contain themselves as members. The subclasses , , and convey different intentions about the relationship between the items in containers.

Because the relationship between , , ⁊·c and is often implicit, and because there is no upper limit to membership properties or restrictions on their length, Containers can be difficult to reason about. Lists are a better solution in most cases.