"ace in the hole" meaning in English

{
  "etymology_text": "From stud poker in which there is one unknown card called the \"hole card\", referring to the optimum \"hole card\" being an ace.",
  "forms": [
    {
      "form": "aces in the hole",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "aces in the hole",
        "head": "ace in the hole"
      },
      "expansion": "ace in the hole (plural aces in the hole)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "American English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "Our ace in the hole left our opponents stupefied; it isn't every day that an NBA star plays street basketball.",
          "type": "example"
        },
        {
          "ref": "2008 July 14, Christopher Nolan, Jonathan Nolan, The Dark Knight, spoken by The Joker (Heath Ledger), Warner Bros. Pictures, DC Comics, Legendary Pictures",
          "text": "You didn't think I'd risk losing the battle for Gotham's soul in a fistfight with you? No. You need an ace in the hole. Mine's Harvey.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Synonym of ace up one's sleeve"
      ],
      "id": "en-ace_in_the_hole-en-noun-PLOcLyDe",
      "links": [
        [
          "ace up one's sleeve",
          "ace up one's sleeve#English"
        ]
      ],
      "raw_glosses": [
        "(US, idiomatic, informal) Synonym of ace up one's sleeve"
      ],
      "synonyms": [
        {
          "tags": [
            "synonym",
            "synonym-of"
          ],
          "word": "ace up one's sleeve"
        }
      ],
      "tags": [
        "US",
        "idiomatic",
        "informal"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "en-au-ace in the hole.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/b/b5/En-au-ace_in_the_hole.ogg/En-au-ace_in_the_hole.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/b/b5/En-au-ace_in_the_hole.ogg",
      "tags": [
        "Australia"
      ],
      "text": "Audio (AU)"
    }
  ],
  "word": "ace in the hole"
}

{
  "etymology_text": "From stud poker in which there is one unknown card called the \"hole card\", referring to the optimum \"hole card\" being an ace.",
  "forms": [
    {
      "form": "aces in the hole",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "aces in the hole",
        "head": "ace in the hole"
      },
      "expansion": "ace in the hole (plural aces in the hole)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "American English",
        "English countable nouns",
        "English entries with incorrect language header",
        "English idioms",
        "English informal terms",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with audio links",
        "English terms with quotations",
        "English terms with usage examples"
      ],
      "examples": [
        {
          "text": "Our ace in the hole left our opponents stupefied; it isn't every day that an NBA star plays street basketball.",
          "type": "example"
        },
        {
          "ref": "2008 July 14, Christopher Nolan, Jonathan Nolan, The Dark Knight, spoken by The Joker (Heath Ledger), Warner Bros. Pictures, DC Comics, Legendary Pictures",
          "text": "You didn't think I'd risk losing the battle for Gotham's soul in a fistfight with you? No. You need an ace in the hole. Mine's Harvey.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Synonym of ace up one's sleeve"
      ],
      "links": [
        [
          "ace up one's sleeve",
          "ace up one's sleeve#English"
        ]
      ],
      "raw_glosses": [
        "(US, idiomatic, informal) Synonym of ace up one's sleeve"
      ],
      "synonyms": [
        {
          "tags": [
            "synonym",
            "synonym-of"
          ],
          "word": "ace up one's sleeve"
        }
      ],
      "tags": [
        "US",
        "idiomatic",
        "informal"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "en-au-ace in the hole.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/b/b5/En-au-ace_in_the_hole.ogg/En-au-ace_in_the_hole.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/b/b5/En-au-ace_in_the_hole.ogg",
      "tags": [
        "Australia"
      ],
      "text": "Audio (AU)"
    }
  ],
  "word": "ace in the hole"
}