MPEG-4 Audio (M4A) is a digital audio container format derived from the MP4 format. It is commonly used to store audio data encoded with AAC or ALAC codecs, offering high-quality sound and efficient compression. It is widely supported by Apple's iTunes and other digital music platforms.

The MPEG-4 Audio (M4A) format was developed by the Moving Picture Experts Group (MPEG) and was first introduced in 2001 as part of the MPEG-4 standard. It was designed to improve upon the older MP3 format by offering better sound quality at lower bit rates. The M4A format gained significant traction with Apple's adoption of it in iTunes and the iTunes Store, where it became the default format for audio files. The format supports both lossy (AAC) and lossless (ALAC) compression. The success of Apple's iTunes and the widespread use of iPods and iPhones contributed significantly to the popularity of the M4A format.