namespaces In XML, a namespace is an abstract domain to which a collection of element and attribute names can be assigned. The namespace name is a character string which must adhere to the generic URI syntax. However, the name is generally not considered to be a URI, because the URI specification bases the decision not only on lexical components, but also on their intended use. A namespace name does not necessarily imply any of the semantics of URI schemes; for example, a namespace name beginning with http: may have no connotation to the use of the HTTP. Originally, the namespace name could match the syntax of any non-empty URI reference, but the use of relative URI references was deprecated by the W3C. A separate W3C specification for namespaces in XML 1.1 permits Internationalized Resource Identifier (IRI) references to serve as the basis for namespace names in addition to URI references. See also CURIE Linked data Extensible Resource Identifier Internationalized Resource Identifier (IRI) Internet resource locator Persistent uniform resource locator Uniform Naming Convention Resource Directory Description Language Universally unique identifier List of URI schemes Notes References Further reading External links URI Schemes – IANA-maintained registry of URI Schemes URI schemes on the W3C wiki Architecture of the World Wide Web, Volume One, §2: Identification – by W3C W3C URI Clarification Application layer protocols Internet protocols Internet Standards URL