- noun a device used to remove unwanted magnetic fields from a disk, tape or recording head
- A circuit or device which removes magnetism. For instance, a circuit or device which demagnetizes a color TV picture tube or a recordable magnetic medium.
- A device which utilizes a strong magnetic field to erase all information from a recordable magnetic medium, such as a reel of magnetic tape or a floppy disk. In the case of a reel of magnetic tape, for instance, the use of such a device avoids the need for having to run the entire tape past the erase head. Also called bulk eraser.