Find the word definition

Wiktionary
click track

n. (lb en music) A series of audio cues used to synchronize sound recordings, sometimes to a moving image.

Wikipedia
Click track

A click track is a series of audio cues used to synchronize sound recordings, sometimes for synchronization to a moving image. The click track originated in early sound movies, where optical marks were made on the film to indicate precise timings for musical accompaniment. It can also serve a purpose similar to a metronome, as in the music industry, where it is often used during recording sessions and live performances.