1) A metallic element found in certain minerals, in nearly all soils, and in mineral waters. It has the atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of hemoglobin, cytochrome, and other components of respiratory enzyme systems. Its chief functions are in the transport of oxygen to tissue (hemoglobin) and in cellular oxidation mechanisms. Depletion of iron stores may result in iron-deficiency anemia. Iron is used to build up the blood in anemia. (From Dorland, 27th ed)

2) A heavy malleable ductile magnetic silver-white metallic element that readily rusts in moist air, occurs native in meteorites and combined in most igneous rocks, is the most used of metals, and is vital to biological processes (as in transport of oxygen in the body) -- symbol Fe.

3) Iron chemically combined .