A Description Logic (DL) models concepts, roles and individuals, and their relationships.The fundamental modeling concept of a DL is the axiom - a logical statement relating roles and/or concepts. This is a key difference from the frames paradigm where a frame specification declares and completely defines a class.

The description logic community uses different terminology than the first-order predicate logic community for operationally-equivalent notions; some examples are given here:

FOL vs DL class - concept property or predicate - role object - individual

The Web Ontology Language [OWL] mostly uses FOL terminology, in spite of being an implementation of a description logic.