iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple for its iPhone line of smartphones. It was unveiled in January 2007 alongside the first-generation iPhone, and was released in June 2007. Major versions of iOS are released annually; the current stable version, iOS 18, was released to the public on September 16, 2024. Besides powering iPhone, iOS is the basis for three other operating systems made by Apple: iPadOS, tvOS, and watchOS.
https://en.wikipedia.org/wiki/IOS