The AAC (Advanced Audio Coding) format is an audio compression standard that provides high-quality sound with efficient file compression. Developed as the successor to MP3, AAC is known for its improved compression efficiency and better sound quality at lower bit rates. It is a widely used audio format for various applications, including mobile devices, online streaming services, and digital media players. AAC files typically offer a good compromise between file size and audio fidelity, making them popular in modern audio applications.