an abstraction belonging to or characteristic of two entities or parts together

an abstraction over files, and Aldat is designed to support programming at this level of abstraction

an entity that connects two or more entities in a specific manner

Synonym for Entity in formalized relational theory.

The modality to relate, between two or among many real entities, where they are ontologically "equivalent" and where no hierarchic relationship exists.

Reference that gives meaning to both the referring entity and also the referent.