OIL
OIL (Ontology Inference Layer or Ontology Interchange Language) can be regarded as an Ontology Infrastructure for the Semantic Web (see paper "OIL: An Ontology Infrastructure for the Semantic Web", IEEE INTELLIGENT SYSTEMS, MARCH/APRIL 2001).
OIL is based on concepts developed in Description Logic (DL).
Much of the work in OIL has now been incorporated into OWL.
See also: Description Logic, DAML, DAML+OIL
