OWL Web Ontology Language Current Status

This page summarizes the relationships among specifications, whether they are finished standards or drafts. Below, each title links to the most recent version of a document.

Completed Work

W3C Recommendations have been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and are endorsed by the Director as Web Standards. Learn more about the W3C Recommendation Track.

Group Notes are not standards and do not have the same level of W3C endorsement.



RIF RDF and OWL Compatibility (Second Edition)

A formal specification for how RIF can be used with RDF and OWL, including the semantics of different ways of importing RDF data and OWL ontologies into RIF rule systems.


OWL 2 Web Ontology Language Mapping to RDF Graphs (Second Edition)


OWL 2 Web Ontology Language New Features and Rationale (Second Edition)

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OWL 2 Web Ontology Language Primer (Second Edition)


OWL 2 Web Ontology Language Profiles (Second Edition)


OWL 2 Web Ontology Language Quick Reference Guide (Second Edition)

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OWL 2 Web Ontology Language RDF-Based Semantics (Second Edition)


OWL 2 Web Ontology Language Structural Specification and Functional-Style Syntax (Second Edition)


OWL 2 Web Ontology Language XML Serialization (Second Edition)


OWL 2 Web Ontology Language Conformance (Second Edition)

This document describes the conditions that OWL 2 tools must satisfy in order to be conformant with the language specification. It also presents a common format for OWL 2 test cases that both illustrate the features of the language and can be used for testing conformance.


OWL 2 Web Ontology Language Direct Semantics (Second Edition)

This document provides the direct model-theoretic semantics for OWL 2, which is compatible with the description logic SROIQ. Furthermore, this document defines the most common inference problems for OWL 2.


rdf:PlainLiteral: A Datatype for RDF Plain Literals (Second Edition)

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OWL 2 Web Ontology Language Document Overview (Second Edition)

This document serves as an introduction to OWL 2 and the various other OWL 2 documents. It describes the syntaxes for OWL 2, the different kinds of semantics, the available profiles (sub-languages), and the relationship between OWL 1 and OWL 2.


OWL Web Ontology Language Overview

The OWL Web Ontology Language is designed for use by applications that need to process the content of information instead of just presenting information to humans. OWL facilitates greater machine interpretability of Web content than that supported by XML, RDF, and RDF Schema (RDF-S) by providing additional vocabulary along with a formal semantics. OWL has three increasingly-expressive sublanguages: OWL Lite, OWL DL, and OWL Full.

This document is written for readers who want a first impression of the capabilities of OWL. It provides an introduction to OWL by informally describing the features of each of the sublanguages of OWL. Some knowledge of RDF Schema is useful for understanding this document, but not essential. After this document, interested readers may turn to the OWL Guide for more detailed descriptions and extensive examples on the features of OWL. The normative formal definition of OWL can be found in the OWL Semantics and Abstract Syntax.


OWL Web Ontology Language Guide

The World Wide Web as it is currently constituted resembles a poorly mapped geography. Our insight into the documents and capabilities available are based on keyword searches, abetted by clever use of document connectivity and usage patterns. The sheer mass of this data is unmanageable without powerful tool support. In order to map this terrain more precisely, computational agents require machine-readable descriptions of the content and capabilities of Web accessible resources. These descriptions must be in addition to the human-readable versions of that information.

The OWL Web Ontology Language is intended to provide a language that can be used to describe the classes and relations between them that are inherent in Web documents and applications.

This document demonstrates the use of the OWL language to

  1. formalize a domain by defining classes and properties of those classes,
  2. define individuals and assert properties about them, and
  3. reason about these classes and individuals to the degree permitted by the formal semantics of the OWL language.

The sections are organized to present an incremental definition of a set of classes, properties and individuals, beginning with the fundamentals and proceeding to more complex language components.


OWL Web Ontology Language Reference

The Web Ontology Language OWL is a semantic markup language for publishing and sharing ontologies on the World Wide Web. OWL is developed as a vocabulary extension of RDF (the Resource Description Framework) and is derived from the DAML+OIL Web Ontology Language. This document contains a structured informal description of the full set of OWL language constructs and is meant to serve as a reference for OWL users who want to construct OWL ontologies.


OWL Web Ontology Language Semantics and Abstract Syntax


OWL Web Ontology Language Test Cases

This document contains and presents test cases for the Web Ontology Language (OWL) approved by the Web Ontology Working Group. Many of the test cases illustrate the correct usage of the Web Ontology Language (OWL), and the formal meaning of its constructs. Other test cases illustrate the resolution of issues considered by the Working Group. Conformance for OWL documents and OWL document checkers is specified.


OWL Web Ontology Language Use Cases and Requirements

This document specifies usage scenarios, goals and requirements for a web ontology language. An ontology formally defines a common set of terms that are used to describe and represent a domain. Ontologies can be used by automated tools to power advanced services such as more accurate web search, intelligent software agents and knowledge management.

Group Notes


Requirements for the Evaluation and Report Language (EARL) 1.0

This document describes the requirements for the scope, design and features of the Evaluation and Report Language (EARL) 1.0. The Evaluation and Report Language is a standardized format to express test results. The primary motivation for developing this language is to facilitate the exchange of test results between Web accessibility evaluation tools in a vendor neutral and platform independent format. It will also provide reusable vocabulary for generic Web quality assurance and validation purposes.


vCard Ontology - for describing People and Organizations

The document describes a mapping of the vCard specification (RFC6350) to RDF/OWL. The goal is to promote the use of vCard for the description of people and organisations utilising semantic web techniques and allowing compatibility with traditional vCard implementations.


OWL 2 RL in RIF (Second Edition)

A detailed explanation of how to implement OWL 2 RL reasoning using RIF Core.


OWL 2 Web Ontology Language Manchester Syntax (Second Edition)

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OWL 2 Web Ontology Language Data Range Extension: Linear Equations (Second Edition)


Defining N-ary Relations on the Semantic Web

In Semantic Web languages, such as RDF and OWL, a property is a binary relation: it is used to link two individuals or an individual and a value. However, in some cases, the natural and convenient way to represent certain concepts is to use relations to link an individual to more than just one individual or value. These relations are called n-ary relations. For example, we may want to represent properties of a relation, such as our certainty about it, severity or strength of a relation, relevance of a relation, and so on. Another example is representing relations among multiple individuals, such as a buyer, a seller, and an object that was bought when describing a purchase of a book. This document presents ontology patterns for representing n-ary relations in RDF and OWL and discusses what users must consider when choosing these patterns.


XML Schema Datatypes in RDF and OWL

The RDF and OWL Recommendations use the simple types from XML Schema. This document addresses three questions left unanswered by these Recommendations: Which URIref should be used to refer to a user defined datatype? Which values of which XML Schema simple types are the same? How to use the problematic xsd:duration in RDF and OWL? In addition, we further describe how to integrate OWL DL with user defined datatypes (in appendix B).


Representing Specified Values in OWL: "value partitions" and "value sets"

Modelling various descriptive "features" (also known variously as "qualities", "attributes" or "modifiers") is a frequent requirement when creating ontologies. For example: "size" may describe persons or other physical objects and be constrained to take the values "small", "medium" or "large"; rank may describe military officers and restricted to a specific list of values depending on the military organisation.  In OWL such descriptive features are modelled as properties whose range specifies the constraints on the values that the property can take on.  This document describes two methods to represent such features and their specified values: 1) as partitions of classes; and 2) as enumerations of individuals.  It does not discuss the use of datatypes to represent lists of values.


Representing Classes As Property Values on the Semantic Web

This document addresses the issue of using classes as property values in OWL and RDF Schema. It is often convenient to put a class (e.g., ) as a property value (e.g., topic or book subject) when building an ontology. While OWL Full and RDF Schema do not put any restriction on using classes as property values, in OWL DL and OWL Lite most properties cannot have classes as their values. We illustrate the direct approach for representing classes as property values in OWL-Full and RDF Schema. We present various alternative mechanisms for representing the required information in OWL DL and OWL Lite. For each approach, we discuss various considerations that the users should keep in mind when choosing the best approach for their purposes.


OWL Web Ontology Language Parsing OWL in RDF/XML

An OWL-RDF parser takes an RDF/XML file and attempts to construct an OWL ontology that corresponds to the triples represented in the RDF. This document describes a basic strategy that could be used in such a parser. Note that this is not intended as a complete specification, but hopefully provides enough information to point the way towards how one would build a parser that will deal with a majority of (valid) OWL ontologies.

For example, we do not discuss the implementation or handling of owl:imports here, nor do we address in depth issues concerned with spotting some of the more obscure violations of the DL/Lite rules.


LBase: Semantics for Languages of the Semantic Web

This document describes a mechanism for providing a precise semantics for the Semantic Web Languages (referred to as SWELs from now on. The purpose of this is to define clearly the consequences and allowed inferences from constructs in these languages.


OWL Web Ontology Language XML Presentation Syntax

This document specifies XML presentation syntax for OWL, which is defined as a dialect similar to OWL Abstract Syntax [OWL Semantics]. It is not intended to be a normative specification. Instead, it represents a suggestion of one possible XML presentation syntax for OWL.


Below are draft documents: other Working Drafts . Some of these may become Web Standards through the W3C Recommendation Track process. Others may be published as Group Notes or become obsolete specifications.

Other Working Drafts


Time Ontology in OWL

The OWL-Time ontology is an OWL-2 DL ontology of temporal concepts, for describing the temporal properties of resources in the world or described in Web pages. The ontology provides a vocabulary for expressing facts about topological relations among instants and intervals, together with information about durations, and about temporal position including date-time information.

Obsolete Specifications

These specifications have either been superseded by others, or have been abandoned. They remain available for archival purposes, but are not intended to be used.



RDF/OWL Representation of WordNet

This document presents a standard conversion of Princeton WordNet to RDF/OWL. It describes how it was converted and gives examples of how it may be queried for use in Semantic Web applications.


Image Annotation on the Semantic Web

Many applications that involve multimedia content make use of some form of metadata that describe this content. The goals of this document are (i) to explain what the advantages are of using Semantic Web languages and technologies for the creation, storage, manipulation, interchange and processing of image metadata, and (ii) to provide guidelines for doing so. The document gives a number of use cases that illustrate ways to exploit Semantic Web technologies for image annotation, an overview of RDF and OWL vocabularies developed for this task and an overview of relevant tools.

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