The announcement was one of several from Apple Monday, including the debut of a refreshed MacBook Air line and a high-powered Mac Pro computer, which will be released later in the year for engineers and graphics designers. Apple also introduced iTunes Radio, a free music streaming service similar to Pandora.
What Cook chose not to unveil were updated versions of the iPhone and iPad or of the popular MacBook Pro laptop computer. A new iPhone presumably will be introduced sometime in the fall.
But the core of the keynote address was about the iPhone's new iOS 7 operating system, which has been redesigned with a completely fresh look that does away with the old style known as "skeuomorphism."
Those design elements replicated everyday household items, such as leather and notebook pads, while the new interface uses flatter icons and more black and white color schemes. The latter also has an animated backdrop for the phone's opening lockscreen and a parallax, faux-3D view of the homescreen when the user tilts the device.
"We wanted to take an experience people know very well and actually add to it to make it more useful, to make it more enjoyable," the operating system's designer, Jony Ive, said in an introduction video.
As well as a new look, the new OS will have added features, such as a center to access all of the device's controls (think brightness and Airplane mode) and a more full-featured Siri voice assistant that will be integrated with Twitter and the online encyclopedia, Wikipedia.
AirDrop is a new feature in the OS that allows a user to share content on the device with friends through email and a variety of social networks. There also will be more features in the operating system that can be integrated into an automobile for hands-free operation, such as making calls, finding directions and playing music.
Perhaps the biggest new feature is the introduction of the iTunes Radio music streaming service. Music lovers can pick radio stations based on groups or genres and listen to a variety of songs based on that station. The service will be free but come with advertisements and will be integrated into the iPhone and iPad's music app.
Other announcements during Apple's keynote Monday:
• The new MacBook Air will come with Intel's latest chip, code named Haswell. With the new processor, the laptop will have much better battery life, up to 12 hours on the 13-inch model. The Air also will have faster WiFi capability and sell for as little as $999 for the 11-inch model and $1,199 for the 13-inch version. The new models went on sale Monday.
• Mac OSX, the operating system for the desktop and laptop computers, was given a new name. Previous versions were named after cats - such as Mountain Lion and Snow Leopard while the new OSX updates will be named after places in California. The first version, OSX 10.9, will be called OSX Mavericks, for the town near Apple's headquarters in Cupertino known for its surfing.
The new version will include battery-saving features, a revised Safari Web browser and the ability to remember the user's different logins and passwords through an encrypted system. It also will have improved support for multiple displays.
• For professionals such as video editors, graphics artists and engineers, Apple has finally refreshed its Mac Pro line of desktop computers. The new computer for high-end work is in a smaller cylindrical black case, sports a new Intel workstation processor and up to two graphics processors. It will become available later this year and is the first update to the Mac Pro in several years.
• Apple's suite of office-related software, iWork, will be available in a cloud-based version that works with a Web browser. The suite includes the Pages word processor, Numbers spreadsheet program and Keynote presentation software, where all of the documents will be stored in the cloud. The new version will be available later this year. Key changes, updates
New iOS interfaces
New device control center
More full-featured Siri voice assistant
New feature to allow user to share content with friends
Refreshed Mac Pro line of desktop computers
Creation of iTunes Radio music streaming service, similar to Pandora