In the context of music, Synchronization, often shortened to “Sync,” refers to the process of matching a piece of music with a moving image, such as in films, TV shows, advertisements, video games, or online videos.
A critical component of Sync is the Synchronization License. This is the legal agreement between the rights holder of a piece of music (usually the songwriter or music publisher) and a client (such as a movie studio, advertising agency, or broadcaster) who wishes to use that music in sync with visual media.
Sync Licensing has become an increasingly important revenue stream for artists, songwriters, and music publishers, particularly in the age of streaming and digital media.
For more comprehensive information, you can visit the Synchronization Rights page on Wikipedia.