From http://www.w3schools.com (Copyright Refsnes Data)

Introduction to OWL

OWL is a language for processing web information.

What You Should Already Know

Before you study OWL you should have a basic understanding of XML, XML Namespaces and RDF.

If you want to study these subjects first, please visit:

W3Schools' XML Tutorial and RDF Tutorial.

What is OWL?

OWL stands for Web Ontology Language
OWL is built on top of RDF
OWL is for processing information on the web
OWL was designed to be interpreted by computers
OWL was not designed for being read by people
OWL is written in XML
OWL has three sublanguages
OWL is a W3C standard

What is Ontology?

Ontology is about the exact description of things and their relationships.

For the web, ontology is about the exact description of web information and relationships between web information.

Why OWL?

OWL is a part of the "Semantic Web Vision" - a future where:

Web information has exact meaning
Web information can be processed by computers
Computers can integrate information from the web

OWL was Designed for Processing Information

OWL was designed to provide a common way to process the content of web information (instead of displaying it).

OWL was designed to be read by computer applications (instead of humans).

OWL is Different from RDF

OWL and RDF are much of the same thing, but OWL is a stronger language with greater machine interpretability than RDF.

OWL comes with a larger vocabulary and stronger syntax than RDF.

OWL Sublanguages

OWL has three sublanguages:

OWL Lite
OWL DL (includes OWL Lite)
OWL Full (includes OWL DL)

OWL is Written in XML

By using XML, OWL information can easily be exchanged between different types of computers using different types of operating system and application languages.

OWL Example (Airport)

OWL Resource: http://www.daml.org/2001/10/html/airport-ont

Class: Airport

Properties:

Produced using dumpont2.java

OWL is a Web Standard

OWL became a W3C (World Wide Web Consortium) Recommendation in February 2004.

A W3C Recommendation is understood by the industry and the web community as a web standard. A W3C Recommendation is a stable specification developed by a W3C Working Group and reviewed by the W3C Membership.