R·D·F Schema introduces itself as providing “a data‐modelling vocabulary for R·D·F data”. This is correct, but it is important to understand that it performs this function in two different ways :⁠—

It provides properties for modelling R·D·F vocabularies in terms of classes, properties, literals, and the relationships between them.

It provides data structures which are useful for representing data in R·D·F, and a few additional utility properties for expressing common concepts.

The terms in the first category are effectively subsumed within , and are not defined here (they are axiomatic). The terms in the second category, on the other hand, are all given definitions in this ontology as they are broadly useful. In addition to being defined within the core rdfs: name·space, R·D·F Schema also provides the formal definition for many terms in the rdf: one.