What is Siri?

Siri /ˈsɪri/  is a built-in "intelligent personal assistant" and “knowledge navigator”  that enables users of Apple Inc.'s iOS, watchOS and tv OS.
The feature uses a natural language user interface to answer questions, make recommendations, and perform actions by delegating requests to a set of Web services.

Siri can work across multiple iPhone and iPad apps as needed in order to accomplish its tasks. It also supports extended dictation, enabling users to have their words translated into text for use in e-mail and text messages, Facebook status updates, tweets, note-taking Web searching and similar operations.

Siri can perform as both software and a service, since all of your questions and commands are instantly uploaded to Siri's secure servers, and the appropriate actions and responses are sent back down to the iPhone.

The intelligent application even tells a joke or two, which can be amusing and entertaining. Whether used for work or play, the supportive features of Siri can handle the tasks of even the busiest people in today's technology-driven world.