The concept of "type" is fundamental to ODP systems; the interaction model of ODP-RM involves strongly-typed interactions. This Recommendation | International Standard: — defines a framework for describing types of interest in ODP systems by determining what entities need to be typed and what needs to be said about the identified types. The primary focus of this work is the computational interface type system; — identifies and characterizes type languages sufficient to describe the types identified above in an informative annex; — provides enterprise, information, and computational specifications of a generic type repository function within the type description framework which can be specialized to select a specific type system or type notation. The type repository function provides: • storage and retrieval of type descriptions; • management of type descriptions; • management of the relationship between types including matching of types; • naming of types (in a manner consistent with ODP Naming Framework); • interworking and federation of different type repositories. This Recommendation | International Standard provides a standard method of accessing type descriptions used within open distributed processing systems, where the type descriptions can be in various concrete syntaxes and type languages used in these open distributed processing systems. This Recommendation | International Standard also facilitates the dynamic matching of types for interactions, binding and trading purposes.