MP3

Abbreviation for 'MPEG-2 Layer 3'.

A compression standard developed by the Moving Picture Experts Group, a joint committee of the ISO and IEC, specifically for encoding digital audio in a space-efficient manner.

The MP3 file format has become popular because it can store audio with a compression of about 1/10th the size of the original (uncompressed) file. This is achieved by eliminating sounds the human ear can't hear or doesn't easily pick up.