XML terminology

The following is a list of important XML-related terms and definitions.

attribute: A name and its value which are included inside an XML tag. For example, in the tag <book isbn="0-395-73679-X">, isbn is the name and its value is 0-395-73679-X (values are enclosed in single or double quotes).

Cascading Style Sheet (CSS): A style sheet that defines the appearance of an XML or HTML document directly on the client.

child: An XML element located inside another XML element.

content model: In XML, the expression specifying what elements and data are allowed within an element.

Document Type Declaration: A declaration that contains, or points to, a Document Type Definition (DTD).

Document Type Definition (DTD): A collection of markup declarations contained in a single, or multiple XML files, that describes an XML document's permissible elements and structure. A DTD ensures that a uniform structure will be used across all documents.

DTDless: Refers to an XML file with no DTD. A browser processes the XML document structure while it's reading the document because it has no DTD to define the structure in advance.

DXL: Domino® Extension Language. DXL is the representation of Domino design elements as XML using the Domino DTD.

element: A block of text in an XML document made up of a start and end tag, and the content between the tags. Empty tags are also elements. For example, <price>$12.60</price> and <price/> are both elements.

encoding attribute: An attribute inside the XML declaration that indicates the level of encoding in the document. For example, <?xml version="1.0" encoding="UTF-8"> indicates that a compressed form of unicode will be used that assigns one byte for ascii characters, two bytes for other common characters, and three bytes for all other characters.

Hypertext Markup Language (HTML): A markup language consisting of predefined tags used to describe a document's structure and appearance.

parent: An XML element which contains another XML element. The XML element contained by the parent is the child element.

root element: The element that contains all of the other elements in an XML document.

schema: A technology-neutral term for the definition of the structure of an XML document.

SGML: Standard General Markup Language. A markup language which serves as the basis for XML.

standalone attribute: An optional attribute inside an XML declaration that indicates whether the complete XML document is contained in the current file, or if it needs to import other files. For example, <?xml version="1.0" standalone="yes"?>.

style: Defines the characteristics of an element's appearance such as font, boldface, italics.

stylesheet: A document specifying the style information for another document.

valid XML: XML that meets the constraints defined by its Document Type Declaration.

version attribute: An attribute inside the XML declaration that indicates the version number of the XML specification a document conforms to. For example, <?xml version="1.0"?>.

well-formed XML: An XML document is well-formed if there is one root element, and all its child elements are nested within each other. Start tags must have end tags, and each empty tag must be designated as such with a trailing slash (<emptyTag/>). Also all attributes must be quoted, and all entities must be declared.

XML: Extensible Markup Language. A standard for building markup languages.

XML application: A markup language created with XML.

XML declaration: The processing instruction that identifies a document as an XML document and contains the version attribute and the optional standalone and encoding attributes. An XML declaration is the first line in an XML document.

XSLT: Extensible Stylesheet Language Transformations. An XML application that defines how an XML document will be transformed from one form of XML to another. XSLT is commonly used to transform XML data to HTML for rendering on a client.