Definition
Describing materials, such as iron, nickel, cobalt, and their alloys, that are strongly attracted to magnets and can themselves be magnetized to retain a magnetic field.
Plain English
A ferromagnetic material is one that a magnet pulls on strongly and that can also be turned into a magnet itself. Iron and steel are the everyday examples.
Context Anchor
Seen in aircraft maintenance discussions about magnetism, magnet-based crack checks, and compass interference.
Derivation
From Latin ferrum meaning 'iron,' combined with 'magnetic.' The name reflects that iron is the classic example of this kind of material — if it behaves like iron does around a magnet, it's ferromagnetic.
Why Pilots Care
Ferromagnetic parts near magnetic compasses or sensors can create deviation errors that affect navigation accuracy if not identified and corrected during maintenance.
Analogy
A steel paper clip is ferromagnetic: a magnet grabs it easily. An aluminum drink can is not strongly grabbed in the same way.
Intuition Check
Do not assume all metal is ferromagnetic. Many metals are not strongly attracted to a magnet; ferromagnetic materials are the ones that are strongly pulled by a magnet and can become magnetized.
Example Sentence 1
The technician kept ferromagnetic tools clear of the cockpit while swinging the compass to avoid introducing errors.
Example Sentence 2
Aircraft engine mounts sometimes contain ferromagnetic alloys that must be demagnetized after heavy maintenance.