meltdownとは 意味・読み方・使い方

語源

From melt (verb) +‎ down (adverb), a deverbal from melt down (verb).

発音

• (Received Pronunciation) IPA: /ˈmɛltdaʊn/
• (Standard Southern British) IPA: /ˈmɛltdawn/
• (General American) IPA: /ˈmɛltˌdaʊn/
• ハイフネーション: melt‧down

名詞

meltdown (countable and uncountable, plural meltdowns)

1. (countable) An act or process of melting.
   1. (nuclear energy, uncountable) Severe uncontrolled overheating and melting of the fuel in the core of a nuclear reactor, with the potential for radiation to escape; (countable) an instance of this.
      • 1986 May 12, John Greenwald, “Deadly Meltdown”, in Time‎, New York, N.Y.: Time Inc., →ISSN, →OCLC, archived from the original on 21 May 2025:

        Thus began by far the gravest crisis in the troubled, 32-year history of commercial atomic power. A catastrophe had occurred over the weekend at the Chernobyl plant, 80 miles north of Kiev, where a reactor meltdown and explosion caused untold death and suffering and raised the prospect of long-term health and environmental damage on a far greater scale than anything yet unleashed by peaceful nuclear use.

2. (countable, rare) A mass of melted material.
3. (originally US, figurative)
   1. (uncountable) Chiefly preceded by a descriptive word: uncontrolled disorder which often has disastrous consequences; (countable) a situation involving this; a crisis.
      • 2001, James Wickham, “Perv spoof bosses axe wrestling”, in Peter Hill, editor, Daily Star, London: Reach plc, →ISSN, →OCLC, column 1:

        Channel 4 switchboards went into meltdown this week when viewers called to complain about a Brass Eye programme on child sex.

      • 2004 November 27, Barrie Clement, “Computer meltdown baffles the experts”, in The Independent‎, London: Independent News & Media, →ISSN, →OCLC, archived from the original on 9 December 2004:

        Computer engineers were at a loss last night to explain why the Government had been hit by arguably the worst electronic meltdown in the history of Whitehall.

      • 2019 August 30, Jackie Flynn Mogensen, “One Very Bad Habit is Fueling the Global Recycling Meltdown”, in Mother Jones‎, San Francisco, Calif.: Foundation for National Progress, →ISSN, →OCLC, archived from the original on 26 February 2021:

        If you're like me, you've looked at a paper coffee cup or an empty tube of toothpaste and thought, "Is this recyclable?" before tossing it in the recycling bin, hoping someone, somewhere, would sort it out. People in the waste management industry call this habit "wishcycling." […] [W]ishcycling is playing a big role in the current global recycling meltdown. […] Our uncertainty leads to climbing costs and waning productivity at recycling facilities; […]

      1. (countable, finance) Synonym of crash (“a sudden large decline in the value of money, stocks or other assets, etc., especially one that causes additional economic difficulties”).
   2. (informal, uncountable) (Sudden) loss of control over one's behaviour, emotions, etc.; (countable) an instance of this.

      Synonym: (Internet slang) melty

      1. (countable) An emotional outburst; a fit, a tantrum.

         Synonyms: see Thesaurus:tantrum

      2. (countable, autism) A response to sensory overload or stress, in which an autistic person is overwhelmed by intense, seemingly disproportionate emotions, behaving erratically and becoming unable to mask (“act more neurotypically”).
         • 2016, Jeanette Purkis, Emma Goodall, Jane Nugent, quoting Laura, “Diagnosis”, in The Guide to Good Mental Health on the Autism Spectrum, London; Philadelphia, Pa.: Jessica Kingsley Publishers, →ISBN, page 26:

           I was diagnosed with Asperger's syndrome in my forties. […] Now if I am really anxious, I can take a moment to think about what is making me anxious and what to do about it; before I would just spiral into a meltdown really quickly, with no understanding of why.

         • 2020, Bill Nason, “Shutdowns and Meltdowns”, in The Autism Discussion Page on Stress, Anxiety, Shutdowns and Meltdowns: Proactive Strategies for Minimizing Sensory, Social and Emotional Overload, London; Philadelphia, Pa.: Jessica Kingsley Publishers, →ISBN, page 171:

           As the brain starts becoming overwhelmed with stress chemicals, it has two primary ways of responding. […] [I]f the accumulation of stress chemicals, stimulation and/or demands are occurring too fast or are too intense to block out, then a meltdown is probable.

         • 2022, Barb Cook, Yenn Purkiss, “What is Advocacy and Why Do We Need It?”, in The Autism and Neurodiversity Self Advocacy Handbook: Developing the Skills to Determine Your Own Future, London: Jessica Kingsley Publishers, →ISBN, page 33:

           If you're experiencing challenges that are extremely stressful and may lead you to being overwhelmed, or set off a meltdown in the workplace, this may be very concerning to your work colleagues.

      3. (countable, psychology) Synonym of nervous breakdown (“an attack of a psychological disorder such as anxiety or depression which is so severe that it prevents a person from continuing to function normally”); also (loosely), a situation where one is unable to function mentally due to panic, stress, etc.

         (psychology): Synonym: mental breakdown

         • 2006, Ercille Christmas, “Thursday, 7/11/02”, in Thoughts of a Proud American: An Ode to “Joe and Josephine Ordinary, Salt of the Earth Americans”, Bloomington, Ind.; Milton Keynes, Buckinghamshire: AuthorHouse, →ISBN, page 285:

           I had a major meltdown at work today. After being instructed one more time about additional work that I was to delegate to my direct reports, I snapped, but in a very polite manner. I excused myself from the boss' office and broke down completely in my cubicle.

         • 2025 January 27, Alexandra Carlton, “The kindness of strangers: I pulled over in hysterics – then a passing driver saved me from the spider”, in Katharine Viner, editor, The Guardian‎, London: Guardian News & Media, →ISSN, →OCLC, archived from the original on 27 January 2025:

           After the huntsman raced across my windscreen, I had an arachnophobic meltdown on the side of the road.

派生語

関連する語

• melt down

派生した語

• → Japanese: メルトダウン (merutodaun)

参考

• China syndrome

参照

Further reading

• nuclear meltdown on Wikipedia.Wikipedia
• meltdown (disambiguation) on Wikipedia.Wikipedia

動詞

melt down (third-person singular simple present melts down, present participle melting down, simple past melted down, past participle melted down or (archaic) molten down)

1. (transitive) To melt fully, especially metal or glass so that it can be remade into something else.
   • 2021 December 1, Nigel Harris, “St Pancras and King's Cross: 1947”, in RAIL, number 945, page 39:

     The Great Exhibition of 1851 is also very much in King's Cross's DNA. The clock in its short, Italianate central tower came from the Exhibition and in its early years it struck the hours, but the bells were first silenced in the First World War and then melted down during the Second World War.

2. (intransitive) To lose structure by being heated to a molten state.

   The reactor core melted down.

3. (intransitive, figuratively) To have a breakdown; to collapse or fail utterly.

派生語