7.9. The import Element
One XML schema can appropriate components from another XML schema that has a different namespace. An import element identifies a schema (usually by identifying a schema document that represents it) using a different namespace, and generates equivalent components in the new schema. The components retain their original namespace in the new schema.
An include element adds components from another schema, with a different namespace, to the current schema. An import element adds components from another schema, but associates them with the target namespace.
Section 6.15 provides a complete discussion on how the namespace and schemaLocation attributes affect locating schema components. The following list is a brief overview ...