"0-dark-thirty" meaning in English

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  "lang_code": "en",
  "pos": "noun",
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        {
          "ref": "2002, Jonathan Shay, Odysseus in America: Combat Trauma and the Trials of Homecoming",
          "text": "In the very early morning--0-dark-30--the veterans have the Wall entirely to themselves, which is the main reason that we go at that hour.",
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      "glosses": [
        "Half an hour past 12(am) midnight, or more formal and exact would be 00:30; The practice of adding “dark” and “thirty” (30) can be used sometimes as a slang term in place of an otherwise specific time a time of night, meaning some time when it is dark out between 00:01 - 05:00 hours local time."
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        "(chiefly US military slang) Half an hour past 12(am) midnight, or more formal and exact would be 00:30; The practice of adding “dark” and “thirty” (30) can be used sometimes as a slang term in place of an otherwise specific time a time of night, meaning some time when it is dark out between 00:01 - 05:00 hours local time."
      ],
      "related": [
        {
          "word": "0-dark-hundred"
        },
        {
          "word": "dark thirty"
        },
        {
          "word": "oh dark hundred"
        },
        {
          "word": "oh dark thirty"
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        {
          "word": "zero dark thirty"
        },
        {
          "word": "dark o’clock"
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          "word": "beer o'clock"
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      "synonyms": [
        {
          "word": "stupid o'clock"
        },
        {
          "word": "wee small hours"
        },
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          "word": "early morning"
        }
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  "word": "0-dark-thirty"
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      "word": "0-dark-hundred"
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      "word": "dark thirty"
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      "word": "oh dark thirty"
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      "word": "zero dark thirty"
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      "word": "dark o’clock"
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          "ref": "2002, Jonathan Shay, Odysseus in America: Combat Trauma and the Trials of Homecoming",
          "text": "In the very early morning--0-dark-30--the veterans have the Wall entirely to themselves, which is the main reason that we go at that hour.",
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        "Half an hour past 12(am) midnight, or more formal and exact would be 00:30; The practice of adding “dark” and “thirty” (30) can be used sometimes as a slang term in place of an otherwise specific time a time of night, meaning some time when it is dark out between 00:01 - 05:00 hours local time."
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        "(chiefly US military slang) Half an hour past 12(am) midnight, or more formal and exact would be 00:30; The practice of adding “dark” and “thirty” (30) can be used sometimes as a slang term in place of an otherwise specific time a time of night, meaning some time when it is dark out between 00:01 - 05:00 hours local time."
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  "synonyms": [
    {
      "word": "stupid o'clock"
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    {
      "word": "wee small hours"
    },
    {
      "word": "early morning"
    }
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  "word": "0-dark-thirty"
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