802.11: An industry standard for a type of wireless computer LAN.

AAC: An acronym for Advanced Audio Codec. AAC is the default audio codec format used by Apple's iTunes Music Store.

accessories: Supporting devices (such as universal remote controls, touchpads, or digital media adapters) that make the content in your home theater accessible from another location.

analog: A type of telecommunications signal (audio or video) that is translated into electronic pulses with varying strength or frequency.

aspect ratio: The width of a video display compared to its height and defined as a ratio, such as 16:9 for widescreen and 4:3 for a traditional TV.

ATSC: A technical standard developed by the Advanced Television Systems Committee that is synonymous with digital TV, or DTV. HDTV is a subset of ATSC.

attentuation: The weakening of an audio signal as it travels over a cable. Use the shortest cables possible to lessen sound degradation in a home theater.

audio sources: Devices in a home theater system that provide audio-only playback, such as CD players/recorders, AM/FM tuners, satellite radio tuners, audio cassette players, and turntables.