"Right so as whil that Iren is hoot men sholden smyte." [Chaucer, c.1386]To have (too) many irons in the fire "to be doing too much at once" is from 1540s. Iron lung "artificial respiration tank" is from 1932.
iron i·ron (ī'ərn)
Symbol Fe A lustrous, malleable, ductile, magnetic or magnetizable metallic element. Atomic number 26; atomic weight 55.847; melting point 1,538°C; boiling point 2,860°C; specific gravity 7.874 (at 20°C); valence 2, 3, 4, 6.
A pill or other medication containing iron and taken as a dietary supplement.
|iron (ī'ərn) Pronunciation Key
A silvery-white, hard metallic element that occurs abundantly in minerals such as hematite, magnetite, pyrite, and ilmenite. It is malleable and ductile, can be magnetized, and rusts readily in moist air. It is used to make steel and other alloys important in construction and manufacturing. Iron is a component of hemoglobin, which allows red blood cells to carry oxygen and carbon dioxide through the body. Atomic number 26; atomic weight 55.845; melting point 1,535°C; boiling point 2,750°C; specific gravity 7.874 (at 20°C); valence 2, 3, 4, 6. See Periodic Table. See Note at element.