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

Someone once thought that butter, brown sugar, and pineapple should cook together at the bottom of a cast-iron skillet to make a deliciously gooey topping for a cake when flipped over. —Kaitlyn Yarborough, Southern Living, 30 Apr. 2026

For a large, thick cast-iron skillet, electric burners are terrible for evenly distributing heat and keeping oil hot. —Jack Hennessy, Outdoor Life, 29 Apr. 2026

Noun

The kitchen is most impressive with its modern appliances, contemporary layout and a historic cast iron wood-burning stove. —James Alexander, Hartford Courant, 26 Apr. 2026

Historic details, including a decorative fireplace, parquet floors, and cast iron radiators add charm to the sunny maison. —Katie Schultz, Architectural Digest, 23 Apr. 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
• chitosan
• cynodon
• denouement
• deuteron
• echelon

Kids Definition

cast iron

noun

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