Definition:
Sync or Syncing - Syncing is the process by which data is moved from a computer to an iPod.
iPod Syncing is employed when users want to add or remove content - songs, albums, movies, TV shows, podcasts, etc. - to their iPods. It is used to synchronize (thus the term sync) the contents of the iTunes library on the computer and the iPod library on the device.
Syncing is performed by connecting the iPod to the computer using the iPod cable. Syncing is usually automatically initiated when the iPod is connected.
