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

Best Father’s Day gift for Iron Man is a cast-iron skillet of a different size that is not part of his collection, a trusty instant read thermometer, or silicon pot-handle covers. —Catharine Kaufman, San Diego Union-Tribune, 29 May 2026

Heat a cast-iron pan until very hot, and add the olive oil. —ABC News, 27 May 2026

Noun

Be sure to place foil on the bottom rack of the oven to catch any spills, and your cast iron will come out as good as new. —Katherine McLaughlin, Architectural Digest, 4 June 2026

One cast iron or carbon steel skillet for high-heat searing, baking and low-and-slow braising. —Ryan Brennan june 2, Fort Worth Star-Telegram, 2 June 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