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 music synchronization permit, or "sync" for brevity, is a license granted by the copyright owner of a specific composition, enabling the licensee to synchronize ("sync") music with various visual media outputs (movies, TV shows, commercials, video games, website soundtracks, movie trailers, etc.).