- the file extension for MPEG Audio Layer-3, a set of standards for compressing and downloading audio files from the internet.
- a file compressed in this format.
- MPEG-1 Audio Layer-3: tradename for software created by the Motion Picture Experts Group that enables files to be compressed quickly to 10% or less of their original size for storage on disk or hard drive or esp for transfer across the internet
- an audio or video file created in this way
