In XQuery, there are seven kinds of nodes: element, attribute, text, namespace, processing-instruction, comment, and document nodes. XML documents are treated as tree of nodes. The root of the tree is called the document node or root node.

Look at the XML document which is given below:

Example of nodes in the XML document above:

Atomic values are nodes with no parent or children.

Example of the atomic values:

Element nodes may have zero, one or more than one children.

In the example which is given below; the title, author, year, and price elements are all children of the book element

Nodes that have the same parent is called siblings.

In the example given below; the title, author, year, and price elements are all siblings:

A node's parent, parent's parent, etc. is called ancesters.

In the example given below; the ancestors of the title element are the book element and the bookstore element:

A node's children, children's children, etc. is called descendants.

In the example given below; descendants of the bookstore element are the book, title, author, year, and price elements