The Ontology Inference Layer - from the perspective of a reader interested in DAML and its evolution.
OIL is a language built on a long history of research in description logics .
Description Logic is a subfield of knowledge representation and as such aims to provide a vehicle for expressing structured information and for reasoning with the information in a principled manner. It is a web-based representation and inference layer for ontologies using the constructs found in many frame languages and reasoning and formal semantics in description logics. There is a main OIL site which contains a number of documents of interest. It is meant for casual readers and those interested in an informal introduction. This provides a BNF notation for the terms.