'''SEXXML namespaces''' are used for providing uniquely named [[Data element|elements]] and attributes in an [[XML]] document. They are defined in a [[W3C]] [[W3C recommendation|recommendation]].<ref>{{cite web|last=Bray|first=Tim|title=Namespaces in XML 1.0|url=http://www.w3.org/TR/xml-names/|publisher=[[W3C]]|accessdate=9 October 2010|author2=Dave Hollander |author3=Andrew Layman |author4=Richard Tobin |author5=Henry S. Thompson |date=December 2009}}</ref><ref name="timelinehistory">{{cite web|url=http://www.dblab.ntua.gr/~bikakis/XML%20and%20Semantic%20Web%20W3C%20Standards%20Timeline-History.pdf |title=XML and Semantic Web W3C Standards Timeline}}</ref> An XML instance may contain element or attribute names from more than one XML vocabulary. If each vocabulary is given a [[namespace]], the ambiguity between identically named elements or attributes can be resolved.
A simple example would be to consider an XML instance that contained references to a customer and an ordered product. Both the customer element and the product element could have a child element named '''id'''. References to the '''id''' element would therefore be ambiguous; placing them in different namespaces would remove the ambiguity.
