Siri is a computer program that works as an intelligent personal assistant and knowledge navigator, part of Apple Inc.'s iOS, watchOS, macOS, and tvOS operating systems. 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. The software, both in its original version and as an iOS feature, adapts to the user's individual language usage and individual searches (preferences) with continuing use, and returns results that are individualized. Siri was originally introduced as an iOS application available in the App Store by Siri Inc., which was acquired by Apple on April 28, 2010. Siri, Inc. had announced that their software would be available for BlackBerry and for phones running Android, but all development efforts for non-Apple platforms were cancelled after the acquisition by Apple. There are several accent and gender combinations for the voice of Siri.
Siri has been an integral part of iOS since iOS 5 and was introduced as a feature of the iPhone 4S on October 14, 2011. Dictation powered by Siri was added to the third generation iPad with the release of iOS 5.1.1 in May 2012; full Siri support was added with iOS 6. Siri has been included on all mobile Apple hardware manufactured during or after October 2012.
Siri is also integrated into Apple Watch's watchOS, where the feature can be activated by holding down the Digital Crown or by saying "Hey, Siri." Siri is additionally integrated into Apple TV's tvOS, where the feature can be activated using a button on the included Siri Remote.
Since 2014 Siri has been available in some cars via CarPlay, a system that enables the vehicle audio system to be a display and controller for an iPhone. It is available on all iPhones from iPhone 5 with at least iOS 7.1.
Siri was added to the Macintosh with the release of macOS Sierra on September 20, 2016.
On October 8, 2016, Bloomberg reported that Apple was moving Siri, along with other Apple services, to a new system codenamed Pie. Pie gives Apple more control over the system, thus enabling potentially faster and more reliable services.