Question 31 :
What is an XML namespace?
An XML namespace is a collection of element type and attribute names. The collection itself is unimportant -- in fact, a reasonable argument can be made that XML namespaces don't actually exist as physical or conceptual entities . What is important is the name of the XML namespace, which is a URI. This allows XML namespaces to provide a two-part naming system for element types and attributes. The first part of the name is the URI used to identify the XML namespace -- the namespace name. The second part is the element type or attribute name itself -- the local part, also known as the local name. Together, they form the universal name.
This two-part naming system is the only thing defined by the XML namespaces recommendation.