an alloy of iron, carbon, and other elements, cast as a soft and strong, or as a hard and brittle, iron, depending on the mixture and methods of molding.
cast-i•ronPronunciation: (kast'ī'urn, käst'-), [key]
made of cast iron.
not subject to change or exception: a cast-iron rule.
hardy: a cast-iron stomach.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.