(adj.) Short for magneto-optical, a type of data storage technology that combines magnetic disk technologies with optical technologies, such as those used in CD-ROMs. Like magnetic disks, MO disks can be read and written to. And like floppy disks, they are removable. However, their storage capacity can be more than 200 megabytes, much greater than magnetic floppies. In terms of data access speed, they are faster than floppies but not as fast as hard disk drives.