Cast-iron stomach is an interesting idiom. We will examine the meaning of the common idiom cast-iron stomach, where it came from, and some examples of its idiomatic usage in sentences.
Someone is said to have a cast-iron stomach if he is not easily nauseated, can eat almost anything without ill effects, or can stand the sight of disgusting things without feeling ill. Cast iron is an iron-carbon substance that can be poured into molds and is particularly durable. Cast iron is often used for skillets and other cookware. The expression cast-iron stomach came into use in the early 1900s; note that cast-iron is hyphenated in the idiom cast-iron stomach because it is an adjective that appears before a noun.