FLAC (Free Lossless Audio Codec) is an audio format that stores music in a compressed, lossless format. This means that FLAC files are identical to the original audio data, without any loss of quality. FLAC files are popular among audiophiles and music enthusiasts who value high-quality audio. One of the significant advantages of FLAC is that it allows for large music collections to be stored in a relatively small space, making it an excellent choice for portable music players.