Abstract: A method for creating a rights data dictionary for definition of terms of a rights expression language is disclosed. The data dictionary may be used in computer operations on rights expression metadata, such as for digital rights management applications. The data dictionary may also be used for translating between expressions in different rights expression languages, thereby enabling interoperability of rights expressions. The rights data dictionary is organized according to a hierarchical schema. Terms are added to the data dictionary according to specified rules that relate to a basic term set, and in particular, are begotten from act type terms. The schema includes a “context” term of the basic term set that is assigned a meaning signifying a circumstance in which at least the basic action occurs. Other terms may be developed from the context term and defined by their relationship to it.