To occur together.
To coordinate or combine.
To cause (a set of files, data, or settings) on one computer or device to be (and try to remain) the same as on another.
To agree, be coordinated with, or complement well.
To set (a clock or watch) to display the same time as another.
To occur at the same time or with coordinated timing.
To cause (video and audio) to play in a coordinated way.