Advanced Audio Coding (also called MPEG-4); a standard way of compressing and encoding digital audio. AAC files can be played using iPod, iPhone, iPad, and apps that support QuickTime.

AAC-encoded files rival the quality of audio CDs, and sound as good as or better than MP3 files encoded at the same or even higher bit rate. For example, a 128 Kbps AAC file should sound as good as or better than a 160 Kbps MP3 file. Because the bit rate is lower, the AAC file will also be smaller than the MP3 file.

AAC files enable you to store the most music on your hard disk or device. At the High Quality setting, AAC files use approximately 1 MB of disk space per minute.


Audio Interchange File Format; an uncompressed and lossless format for digital audio. Use AIFF files to burn high-quality audio CDs from imported songs. AIFF files use approximately 10 MB of disk space per minute.


A way to play music from an iTunes library on multiple speakers or AirPlay-enabled devices over a wireless local network.


A monthly credit that can be used to purchase items from the iTunes Store. Both the allowance purchaser and the recipient must have an Apple ID.

Apple Lossless

An Apple-developed method for creating digital music files. Apple Lossless files can be played using apps that support QuickTime, iPhone, iPad, and some iPod models. Use Apple Lossless to listen to songs on audiophile-quality sound systems with no loss of quality, and to burn high-quality audio CDs from imported songs.

Apple Lossless files use approximately 5 MB of disk space per minute.

App Store

A part of the iTunes Store, where you can download apps for iPod touch, iPhone, and iPad.

Apple TV

A device for playing content downloaded from the iTunes Store or from your iTunes library on your home theater system.

Audible website

A website ( that sells audiobooks and other spoken programs. Items purchased from the Audible website can be downloaded to iTunes, and can be played on your computer, iPod, iPhone, or iPad.


A recorded spoken program, such as a book being read aloud. You can purchase and download audiobooks from the iTunes Store and the Audible website.


To enable a computer to play iTunes Store purchases. You can authorize up to five computers at a time.

Note:  A computer can play iTunes Plus songs without authorization.

You can also authorize your computer to play your Audible website purchases.


A portion of music or video that’s temporarily stored on your computer when you stream media content from the Internet. A buffer compensates for variations in connection speed, resulting in smoother playback.


To record songs onto a CD or DVD.


A label issued by the Recording Industry Association of America to identify an edited version of an “explicit” recording.


To start playing the next song while the previous song is still playing.


To prevent an authorized computer from playing iTunes Store purchases. You should do this before you give away or sell your computer.


To transfer files from one computer or system to another; for example, you can download music from the iTunes Store to your computer.


To remove a disc (CD or DVD) from a disc drive, or to remove an iPod, iPhone, or iPad from the list of devices in the iTunes window. To eject a disc or device, click the Eject button Eject icon next to the item.

encoding format

The type of format used to create a digital file. Audio encoding formats include AAC, Apple Lossless, MP3, and others. Video formats include MPEG-4, H.124, and others.


A set of controls for changing sound frequencies (for example, boosting the bass on a rock song) to accommodate speakers, personal taste, and other factors.


A label—issued by media producers—that alerts consumers to content that might be inappropriate for children. See “Clean.”


A feature that enables you to find new music—in your library and in the iTunes Store—related to music already in your library.

Genius Mix

An ongoing playlist in a particular genre—like a commercial-free radio station playing your favorite songs—that iTunes creates from music in your library. iTunes can create up to 12 Genius Mixes.

Genius playlist

A playlist iTunes creates of songs that go great with a song you specify.

Gracenote media database

An online service that contains information about audio CDs. iTunes uses this database to display a CD’s name, song titles, and so on.

Home Sharing

A way to share and import items from up to five iTunes libraries on other computers in your home network. To use Home Sharing, you must have an Apple ID, and all computers in the Home Sharing network must be authorized to play purchases made using that Apple ID.


Apple’s service that stores your music, photos, apps, contacts, calendars, and more, and wirelessly pushes them to all your iOS devices and computers.


To add music, video, and other media to your iTunes library.

iTunes Extras

A unique experience that features exclusive interviews, videos, photos, and more. Available with select movie purchases in the iTunes Store.

iTunes library

The collection of music, videos, and other media you have imported into iTunes.

iTunes Library file

A database of your library’s contents. If you move or delete this file, iTunes creates a new one the next time you open iTunes, but it doesn’t contain playlists, song ratings, comments, and other information you created.

iTunes LP

A unique experience that features exclusive interviews, videos, photos, and more. Available with select album purchases in the iTunes Store.

iTunes Plus

Songs and music videos, available at the iTunes Store, that are encoded in high-quality, 256-Kbps AAC format. There are no burn limits on iTunes Plus items, and they’re free of digital rights management (DRM) limitations. iTunes Plus content can be played on iPod, iPhone, iPad, Apple TV, all Mac and Windows computers, and many other digital music players.

iTunes Store

An online store, accessible through iTunes, where you can purchase music and videos, rent movies, download free podcasts, and more.


The mobile operating system software used by iPhone, iPod touch, and iPad.


An audio format commonly used for digital audio players. MP3 can be played using computers and most digital music players, including iPod, iPhone, and iPad.

MP3 files use approximately 1 MB of disk space per minute.


An option for buying TV shows from the iTunes Store. Designed for shows that don’t have traditional “seasons” (news shows, for example), the Multi-Pass purchases a set number of episodes.

parental controls

Options that enable a computer administrator to limit access to features. In the Parental pane of iTunes preferences, for example, you can prevent someone from accessing the iTunes Store.


A collection of songs or other media (video and podcasts) arranged in a custom order.


A radio- or TV-style show you can download from the Internet for free from the iTunes Store, as well as various websites. Some podcasts are individual episodes; some are series.


Multimedia software from Apple that handles video, sound, text, animation, music, and several types of images available for Mac computers and PCs.


The sound a mobile phone makes when someone calls.


To transfer songs from a CD to a hard disk.

Season Pass

An option for buying TV shows from the iTunes Store. With a Season Pass, all currently available episodes are downloaded to iTunes on your computer. When a new episode is available, you are notified and the show is downloaded. If you’re not connected to the Internet, the episode is put into your iTunes Store download queue, and you can download it the next time you’re online.

shared library

An iTunes library (or a part of one) that’s set up so that others on the local network can play the library’s media files on their own computers.


To play music or video in random order.

Smart Playlist

A playlist to which you assign rules (for example, songs by certain artists); when you add a song to your library that matches your rules, iTunes automatically adds the song to the Smart Playlist.

Sound Check

A setting in iTunes preferences that automatically adjusts songs to play at the same volume level.


To play media on a device without storing the media files on the device. For example, some websites stream movies you can watch on your computer. You can stream items from your iTunes library to your TV, using an Apple TV.

Time Machine

An app included with OS X that automatically backs up the files on your hard disk at regular intervals. For more information, click the desktop and choose Help > Help Center (or Mac Help).


In iTunes, to move a rented movie from one location to another, such as from your iTunes library on a computer to an iPod, iPhone, or iPad.


To update an iPod, iPhone, iPad, or Apple TV so that it contains some or all of the music, video, and other files in your iTunes library.


A program that displays visual effects in the iTunes window.


Waveform; a digital audio format commonly used with Microsoft Windows and computers without MP3 software.

WAV files use approximately 10 MB of disk space per minute.

Wish List

An online directory of iTunes Store items you plan to buy. You can preview and buy items directly from your Wish List. To see your Wish List, click My Wish List below Quick Links in the iTunes Store homepage.


Windows Media Audio; a digital audio file format created by Microsoft. iTunes can convert WMA files to other formats.