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
J. K. Rowling
: 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
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
Jasmine Smith, Southern Living, 30 Sep. 2025
The windowed bathroom, with its cast-iron soaking tub, has an archway for visual interest.
—Matthew Sedacca, Curbed, 29 Sep. 2025
Mariana Best, Better Homes & Gardens, 28 Sep. 2025
It’s constructed with cast iron and coated with a glossy enamel finish that not only delivers impressive heat distribution and retention, but also helps prevent food from sticking to the bottom.
—Alicia Geigel, Southern Living, 25 Sep. 2025
See All Example Sentences for cast-iron
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Adjective
Heat oil in a large cast-iron skillet over high until shimmering.
—Jasmine Smith, Southern Living, 30 Sep. 2025
The windowed bathroom, with its cast-iron soaking tub, has an archway for visual interest.
—Matthew Sedacca, Curbed, 29 Sep. 2025
Noun
With enameled cast iron built to last for many years (and many meals), the Dutch oven is oven safe up to 500 degrees, stain-resistant, and compatible with all cooktops.
—Mariana Best, Better Homes & Gardens, 28 Sep. 2025
It’s constructed with cast iron and coated with a glossy enamel finish that not only delivers impressive heat distribution and retention, but also helps prevent food from sticking to the bottom.
—Alicia Geigel, Southern Living, 25 Sep. 2025
See All Example Sentences for cast-iron
Cite this Entry
“Cast-iron.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cast-iron. Accessed 2 Oct. 2025.
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