From Mac Guides
Apple has used the term SuperDrive on two occasions, once for its DVD burners, and once for its 3.5" Floppy Disk Drives.
SuperDrive is Apple's term for a DVD burner in a Macintosh computer capable of reading and writing DVDs as well as CDs. All current Macs except for Snow Leopard Server Mac mini and the MacBook Air (both have none) have 8x SuperDrives, with the exception of the Mac Pro, which has an 18x SuperDrive.
3.5" Floppy Disk Drive
Previously, Apple referred with the term SuperDrive to their 1.44 MB floppy disk drive.
Later, some people used the term Superdrive to (incorrectly) refer to SuperDisk drives. SuperDrive is an Apple trademark.