magnetic disk
Technical term in computing; refers to a storage medium that uses magnetic patterns to record data, such as a hard disk or floppy disk.
Magnetic disks are used for long-term data storage.
Optical disc (e.g., CD, DVD); uses laser technology rather than magnetism.
Compound of 磁気 (magnetism) and ディスク (disk), a direct calque of English 'magnetic disk'.