1. The recording and reproduction of sound.
2. The part of television or movie equipment that has to do with sound; as opposed to the visual portion (video).
3. The broadcasting, reception, or reproduction of sound.
4. A sound signal: "We lost the audio during the radio broadcast."

The part of any wave or signal whose frequencies are within the audible range.

Any of a wide variety of computer components that accept or produce sound.

The portion of the acoustic energy spectrum, from about 20 to 20,000 vibrations per second, that can be detected by a human with normal hearing.

1. Sound frequency between 20 and 20,000 cycles per second, or hertz; such as, the frequency of normally audible sound waves.
2. A frequency of electrical, sound, or other wave vibrations coming within the range of normal human hearing.

Computer output in the form of simulated or recorded spoken words.

A small flat case containing magnetic tape on two reels, used to record and play back sound and video material: "Very few people are using audiocassettes these days since the introduction of such music sources as Apple i-Tunes and other places that provide on-line music."

Any of various instruments used to measure the frequencies of sound waves that are audible to the human ear.

A reference to the reproduction and transmission of sound stored in a digital format.

This includes CDs as well as any sound files stored on a computer. In contrast, the telephone system (but not ISDN) is based on an analog representation (system that represents changing values as continuously variable physical quantities) of sound.

In sound recording and reproduction systems, digital audio refers to a digital representation of the audio waveform for processing, storage or transmission. When analog sound waves are stored in digital form, each digital audio file can be decomposed into a series of samples.