Link
W3C Recommendation "This document describes the OWL Web Ontology Language. OWL is intended to be used when the information contained in documents needs to be processed by applications, as opposed to situations where the content only needs to be presented to humans. OWL can be used to explicitly represent the meaning of terms in vocabularies and the relationships between those terms. This representation of terms and their interrelationships is called an ontology."
Source
Feb 10 2004, By McGuinness, Deborah L. and Frank van Harmelen, editors