A music synchronization license, or "sync" for short, is a music license granted by the holder of the copyright of a particular composition, allowing the licensee to synchronize ("sync") music with some kind of visual media output (film, television shows, advertisements, video games, accompanying website music, movie trailers, etc.
A sync license is an authorization granted by the composer or publisher of a musical piece, permitting the user to coordinate ("sync") the music with accompanying visuals in films, television programs, advertisements, video games, and other media.