cast-iron

1 of 2

adjective

ˈkast-ˈī(-ə)rn 

1

: made of cast iron

2

: resembling cast iron: such as

a

: capable of withstanding great strain

a cast-iron stomach

b

: not admitting change, adaptation, or exception : rigid

a cast-iron will

c

British : not likely to fail or be broken : airtight

"Clever idea, Black, getting yourself seen on a safe station platform … gave you a cast-iron excuse not to leave your hidey-hole in future, didn't it?"

—J. K. Rowling

cast iron

2 of 2

noun

: a commercial alloy of iron, carbon, and silicon that is cast in a mold and is hard, brittle, nonmalleable, and incapable of being hammer-welded but more easily fusible than steel

Synonyms of cast-iron

Adjective

• strict
• rigorous
• rigid

Examples of cast-iron in a Sentence

Adjective

lost weight only after a cast-iron adherence to his diet

he has a cast-iron faith in his innate ability to overcome any adversity that life might throw against him

Noun

The fence is made of cast iron.

Recent Examples on the Web

Adjective

There are leafy views from the bedrooms and plenty of room to stretch out, and the windowed bathroom feels classic with the cast-iron soaking tub. — Matthew Sedacca, Curbed, 21 Sep. 2026

Heat the oil in your largest nonstick or cast-iron skillet over medium heat until shimmering. — ABC News, 19 Sep. 2026

Noun

Constructed from heavy-gauge cast iron, each piece provides top-notch heat retention and even heat distribution for consistent cooking results—just like similar, pricier cast-iron cookware. — Michele Laufik, Martha Stewart, 28 Sep. 2026

Made from enameled cast iron, this cookware offers stable heat distribution, even heat retention, and is oven-safe from top to bottom (including the lid). — Stephanie Osmanski, Better Homes & Gardens, 19 Sep. 2026

Word History

First Known Use

Adjective

1692, in the meaning defined at sense 1

Noun

1664, in the meaning defined above

Rhymes for cast-iron

• aileron
• antiphon
• autobahn
• carillon
• castellan
• celadon
• cephalon
• cynodon
• denouement
• deuteron
• echelon
• epsilon

Kids Definition

cast iron

noun

: a hard brittle alloy of iron, carbon, and silicon shaped by being poured into a mold while melted