cast iron

plural cast irons · alternative castiron · alternative cast-iron

1. countableuncountableA hard and brittle, but strong, alloy of iron, carbon, and silicon, formed by casting in a mould.

   Cast iron is popular for cookware where an even heating temperature is important.

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   The history of cast iron in railway bridges is much more grimly chequered. Brunel's misgivings were proved prudent, tragically, in the 1879 failure of Thomas Bouch's Tay bridge (once a monument to cast iron, now a memorial to many lives lost).

   2025 March 5, Dr Joseph Brennan, “Remembering Brunel's timber viaducts”, in RAIL, number 1030, page 60

comparative more cast iron · superlative most cast iron · alternative castiron · alternative cast-iron

1. not comparableMade of cast iron.

   I use a cast iron skillet for frying pancakes.

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   Various forms of conductors have been invented, such as wooden and iron pipes, of a round, square, and polygonal section; but at present, scarcely any other than sheet or cast iron pipes are employed.

   1851, Frederick Overman, “Blast Pipes”, in The Manufacture of Iron, in All its Various Branches. […] , 2nd edition, Philadelphia: Henry C. Baird, page 413

   The old black cast iron skillet is an important part of the batterie de cuisine.

   1979 May 28, Ernest Gueymard, “Louisiana's Creole-Acadian Cuisine”, in Renaud S. Albert, editor, A Franco-American Overview, volume 1, →ISBN, page 295

   Three small gelignite bombs, with pocket watch timing devices, were concealed in packets small enough to fit through the slot of the standard cast-iron post box, the cylindrical bright red colored boxes so common throughout London.

   2008, Steven P. Moysey, The Road to Balcombe Street: The IRA Reign of Terror in London, Binghamton, N.Y.: Haworth Press, →ISBN, page 58

2. figurativelyDurable; tough; resilient.

   Ernest has a cast iron constitution and never gets sick.

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   Just because a pilot passes a pretty severe medical test every so often, it doesn't mean that he has a Cast Iron constitution and can fly indefinitely.

   1932 January 28, Charles W. Purcell, “Stop Telling the Pilot What to Do”, in Popular Aviation, volume 10, number 1, →ISSN, page 62

   Synonyms: bulletproof, impervious, iron, robust, unshakable

3. figurativelyInflexible or without exception.

   The school's cast iron policy on admissions fees left no leeway for needy students.

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   "The fact is," confided Tulloch, taking his place in the car, "I've been out of things for a bit, Wynn, and I'm finding civilisation a shade cast-iron now. I've been down in the wilds since you were with me."

   1923, Ernest Bramah [pseudonym; Ernest Brammah Smith], “(please specify the page)”, in The Eyes of Max Carrados, London: Grant Richards, →OCLC

   As far as her own theories are concerned, she is limitlessly credulous, to a degree which makes me suspect that she is a cast-iron idiot.

   2016 March 19, Rod Liddle, “What makes the white working class angry? Twits like Hsiao-Hung Pai”, in The Spectator

   Synonyms: iron-clad, stern, unrelenting, unwavering