a departure from the normal magnetic field of the earth.
noun, Navigation. 1. the bearing of a point relative to that of the nearest magnetic pole.
noun 1. Physics. a magnetic field so shaped that it can confine a plasma: used in a proposed design for fusion reactors. noun 1. a configuration of magnetic fields for containing plasma
noun, Computers. 1. a tiny mobile magnetized area within a magnetic material, the basis of one type of solid-state storage medium (magnetic bubble memory) noun 1. (physics) a small round magnetic domain induced by a magnetic field in a thin film of magnetic material, used in certain types of computer memories
noun 1. . [mag] /mæg/ noun 1. Computers. a plastic or paper card with a magnetizable layer on which data can be recorded and from which data can be read. 2. such a card used in access-control systems, as for automatically unlocking doors.