AAC > Advanced Audio Coding; a standard way of compressing and encoding digital audio

AIFF > Audio Interchange File Format; an uncompressed and lossless format for digital audio

AirTunes > A way to play music in an iTunes library on multiple speakers over a wireless local network, using AirPort Express with iTunes (a hardware device)

allowance > A set monthly amount purchased with an iTunes Store account and given to another account to purchase items in the iTunes Store

App Store > An online store, accessible via the iTunes Store, where you can download applications for iPhone and iPod touch

Apple Lossless > An Apple-developed method for compressing digital music

Apple TV > A device for playing content downloaded from the iTunes Store or from your iTunes library on a television

audiobook > A recorded spoken program, such as a book being read aloud

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

buffer > 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.

burn > To record songs onto a CD or DVD

Clean > A label issued to identify an edited version of an "explicit" recording. See Explicit.

Cover Flow > A way to browse your iTunes library as if you were flipping through actual album covers or movie packages

crossfade > To start playing the next song while the previous song is still playing

deauthorize > To prevent an authorized computer from playing iTunes Store purchases. See authorize.

download > To transfer files from one computer or system to another; for example, to download music from the iTunes Store

eject > To remove a disc (CD or DVD) from a disc drive, or to remove an iPod or iPhone from the list of devices in the iTunes window

equalizer > 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

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

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

Gracenote CDDB > A service that contains information about audio CDs (CDDB stands for "CD database"). iTunes uses this database to display a CD's name, song titles, and so on.

iMix > A playlist a customer publishes for free in the iTunes Store

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

iTunes MiniStore > A part of the iTunes window that displays items in the store related to the selected item; you can click an item in the MiniStore to open it in the iTunes Store.

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

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

MP3 > An audio format commonly used for digital audio players

Multi-Pass > 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 a user from accessing the iTunes Store.

Party Shuffle > A continuously updated playlist iTunes creates from random songs in your library or a playlist. You can change the Party Shuffle playlist.

playlist > A collection of songs or other media (video and podcasts) put in a custom order

podcast > A radio- or TV-style show you can download from the Internet for free from the iTunes Store. Some podcasts are individual episodes; some are series.

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

ringtone > The sound a mobile phone makes when someone calls

rip > 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 put into your iTunes Store download queue.

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

shuffle > 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 the criteria, iTunes automatically adds the song to the Smart Playlist

Sound Check > A setting in iTunes preferences that automatically adjusts songs to the same volume level

stream > To play media on one device while the media files are stored on another 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.

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

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

visualizer > A program that displays visual effects in the iTunes window

WAV > Waveform; a digital audio format commonly used with Microsoft Windows

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