Amazing what you can find with 'Google':

http://www.snia.org/education/dictionary

tape library
A tape device that provides automated access to multiple tape cartridges, typically via multiple tape drives.
An automated tape loading robot is used to move tape cartridges between the tape drives, tape slots (for storage), and tape eject slots if there are any.

tape autoloader
A tape device that provides automated access to multiple tape cartridges, typically via a single tape drive.
An automated tape loading robot may be used to move tape cartridges between the tape drive, tape slots (for storage), and any tape eject slots if there are any.

media stacker
A robotic media handler in which media must be moved sequentially by the robot.
A media stacker usually services a single drive. It may be able to load media into a drive in arbitrary order, but must cycle through media in sequence to do so.

stand alone drive
A removable media drive that is not associated with a media stacker or robot.

robot
robotic media handler
A mechanical handler capable of storing multiple pieces of removable media and loading and unloading them from one or more drives in arbitrary order in response to electronic commands.
See library.
-- for which you can read robotic arm/picker to be the 'part' that does the actual moving!