XPath is a language that describes a way to locate and process items in Extensible Markup Language (XML) documents by using an addressing syntax based on a path through the document's logical structure or hierarchy. This makes writing programming expressions easier than if each expression had to understand typical XML markup and its sequence in a document. XPath also allows the programmer to deal with the document at a higher level of abstraction. XPath is a language that is used by and specified as part of both the Extensible Stylesheet Language Transformations (XSLT) and by XPointer (SML Pointer Language). It uses the information abstraction defined in the XML Information Set (Infoset). Since XPath does not use XML syntax itself, it could be used in contexts other than those of XML.
XPath uses a syntax something like an informal set of directions for finding a particular geographic location. When telling someone how to find the Minneapolis campus of the University of Minnesota within the United States, for example, you might write:
which would put the user in the middle of the campus.
The key difference between XPath and earlier languages is that XPath specifies a route, rather than pointing to a specific set or sequence of characters, words, or other elements.
XPath uses the concepts of the concept node (the point from which the path address begins), the logical tree that is inherent in any XML document, and the concepts expressing logical relationships that are defined in the XML Information Set, such as ancestor, attribute, child, parent, and self. XPath includes a small set of expressions for specifying mathematics functions and the ability to be extended with other functions.