unknown use case term?

[Legacy_Code]

hi,
what are the meanings of the terms "Uses" and "extends" in the use case diagram?

[Kevin Brennan]

Extend: allows for the insertion of additional behavior into a use case. The use case that is being extended must be completely functional in its own right. The extending use case does not need to be complete. Extensions are most often used to encapsulate behavior that may not be present in the initial release of an application—otherwise they may be handled as an alternate flow.

Include: allows for the base use case to make use of functionality present in another use case. The included use case does not need to be a complete use case in its own right. This relationship is most often used when some shared functionality is required by several use cases.

Uses is similar to includes and is not supported in the most recent version of the UML standard.