1.Chemistry . a ductile, malleable, silver-white metallic element, scarcely known in a pure condition, but much used in its crude or impure carbon-containing forms for making tools, implements, machinery, etc. Symbol: Fe; atomic weight: 55.847; atomic number: 26; specific gravity: 7.86 at 20°C. Compare cast iron, pig iron, steel, wrought iron.
2. something hard, strong, rigid, unyielding, or the like: hearts of iron.
3. an instrument, utensil, weapon, etc., made of iron.