Source : Free On-Line Dictionary of Computing

MPEG-1 audio layer 3
     
         (MP3) A {digital audio} {compression
        algorithm} that acheives a compression factor of about twelve
        while preserving sound quality.  It does this by optimising
        the compression according to the range of sound that people
        can actually hear.  MP3 is currently (July 1999) the most
        powerful algorithm in a series of audio encoding standards
        developed under the sponsorship of the {Moving Picture Experts
        Group} (MPEG) and formalised by the International Organization
        for Standardization (ISO).
     
        MP3 is very different from Layer 2, using an additional {MDCT}
        layer to increase frequency resolution.  Its scale factor
        groups are more optimised for the human ear, and it uses
        nonlinear {sample quantisation} and {Huffman coding}.
     
        MP3 files ({filename extension} ".mp3") can be downloaded from
        many {World-Wide Web} sites and can be played using software
        available for most {operating systems} (also downloadable),
        e.g. Winamp for {PC}, MacAmp for {Macintosh}, and mpeg123 for
        {Unix}.
     
        MP3 files are usually downloaded completely before playing but
        {streaming} MP3 is also possible.  A program called a "ripper"
        can be used to copy a selection from a music {CD} onto your
        {hard disk} and another program called an encoder can convert
        it to an MP3 file.
     
        (2001-12-04)