Plain English Meaning

The invisible force that makes magnets stick to iron and makes a compass needle point north. The Earth acts like a giant magnet, and pilots use that fact to find their heading.

Full Definition

A natural physical force produced by moving electric charges (such as electrons) that causes certain materials -- chiefly iron, nickel, and cobalt -- to attract or repel one another and to align with a magnetic field. The Earth itself produces a large-scale magnetic field, and aircraft compasses use this field to indicate direction.

Context Anchor

Seen in instrument flying when learning how a magnetic compass works and why compass headings may not match true geographic north exactly.