Siri is Apple’s voice-recognition service for iOS devices.
Siri responds to users’ spoken questions by speaking back to them and presenting relevant information from certain apps, such as Web Search or Calendar. The service also lets users dictate emails and text messages, and it reads received emails and messages. Some of Siri’s voice-recognition and response processing happens locally on the iOS device, and some takes place in the cloud, depending on the complexity of the user’s request.
In 2010, Apple acquired Siri, Inc., a startup that made a voice-recognition personal assistant app for iPhone and iPad. That acquisition led to the current incarnation of Siri as a native feature on some iOS devices. The service debuted on the iPhone 4S in 2011; in June 2012, Apple announced it would add Siri to the third-generation iPad with the release of iOS 6 and integrate Siri with third-party apps. Siri is not available on earlier versions of the iPhone or iPad.