"million-dollar question" meaning in English

{
  "etymology_text": "From the TV game show Who Wants to Be a Millionaire?, because in the last question the contestants attempt to win a top prize of $1,000,000.",
  "forms": [
    {
      "form": "million-dollar questions",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "million-dollar question"
      },
      "expansion": "million-dollar question (plural million-dollar questions)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2014, Barend Beekhuizen, Rens Bod, Arie Verhagen, “The linking problem is a special case of a general problem none of us has solved: Commentary on Ambridge, Pine, and Lieven”, in Language, volume 90, number 3, page e92",
          "text": "The million-dollar question is what mechanisms and representations (potentially unlearned, potentially domain-specific) exist so that the learner, given the input, gradually comes to behave like an adult language user.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A question that is very important or difficult to answer."
      ],
      "id": "en-million-dollar_question-en-noun-evwHInoq",
      "links": [
        [
          "question",
          "question"
        ],
        [
          "important",
          "important"
        ],
        [
          "difficult",
          "difficult"
        ],
        [
          "answer",
          "answer"
        ]
      ],
      "raw_glosses": [
        "(figurative) A question that is very important or difficult to answer."
      ],
      "synonyms": [
        {
          "word": "billion-dollar question"
        },
        {
          "word": "sixty-four thousand dollar question"
        },
        {
          "word": "sixty-four dollar question"
        },
        {
          "word": "$1,000,000 question"
        },
        {
          "word": "million dollar question"
        }
      ],
      "tags": [
        "figuratively"
      ],
      "translations": [
        {
          "code": "nl",
          "lang": "Dutch",
          "sense": "Translations",
          "tags": [
            "feminine"
          ],
          "word": "hamvraag"
        },
        {
          "code": "fr",
          "lang": "French",
          "sense": "Translations",
          "word": "la question à un million"
        },
        {
          "code": "gl",
          "lang": "Galician",
          "sense": "Translations",
          "word": "a pregunta do millón"
        },
        {
          "code": "de",
          "lang": "German",
          "sense": "Translations",
          "tags": [
            "feminine"
          ],
          "word": "Preisfrage"
        },
        {
          "code": "ru",
          "lang": "Russian",
          "roman": "vopros na million",
          "sense": "Translations",
          "word": "вопрос на миллион"
        },
        {
          "code": "es",
          "lang": "Spanish",
          "sense": "Translations",
          "word": "la pregunta del millón"
        },
        {
          "code": "sv",
          "lang": "Swedish",
          "sense": "Translations",
          "tags": [
            "common-gender"
          ],
          "word": "tiotusenkronorsfråga"
        }
      ],
      "wikipedia": [
        "Who Wants to Be a Millionaire?"
      ]
    }
  ],
  "word": "million-dollar question"
}

{
  "etymology_text": "From the TV game show Who Wants to Be a Millionaire?, because in the last question the contestants attempt to win a top prize of $1,000,000.",
  "forms": [
    {
      "form": "million-dollar questions",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "million-dollar question"
      },
      "expansion": "million-dollar question (plural million-dollar questions)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "Translation table header lacks gloss"
      ],
      "examples": [
        {
          "ref": "2014, Barend Beekhuizen, Rens Bod, Arie Verhagen, “The linking problem is a special case of a general problem none of us has solved: Commentary on Ambridge, Pine, and Lieven”, in Language, volume 90, number 3, page e92",
          "text": "The million-dollar question is what mechanisms and representations (potentially unlearned, potentially domain-specific) exist so that the learner, given the input, gradually comes to behave like an adult language user.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A question that is very important or difficult to answer."
      ],
      "links": [
        [
          "question",
          "question"
        ],
        [
          "important",
          "important"
        ],
        [
          "difficult",
          "difficult"
        ],
        [
          "answer",
          "answer"
        ]
      ],
      "raw_glosses": [
        "(figurative) A question that is very important or difficult to answer."
      ],
      "tags": [
        "figuratively"
      ],
      "wikipedia": [
        "Who Wants to Be a Millionaire?"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "billion-dollar question"
    },
    {
      "word": "sixty-four thousand dollar question"
    },
    {
      "word": "sixty-four dollar question"
    },
    {
      "word": "$1,000,000 question"
    },
    {
      "word": "million dollar question"
    }
  ],
  "translations": [
    {
      "code": "nl",
      "lang": "Dutch",
      "sense": "Translations",
      "tags": [
        "feminine"
      ],
      "word": "hamvraag"
    },
    {
      "code": "fr",
      "lang": "French",
      "sense": "Translations",
      "word": "la question à un million"
    },
    {
      "code": "gl",
      "lang": "Galician",
      "sense": "Translations",
      "word": "a pregunta do millón"
    },
    {
      "code": "de",
      "lang": "German",
      "sense": "Translations",
      "tags": [
        "feminine"
      ],
      "word": "Preisfrage"
    },
    {
      "code": "ru",
      "lang": "Russian",
      "roman": "vopros na million",
      "sense": "Translations",
      "word": "вопрос на миллион"
    },
    {
      "code": "es",
      "lang": "Spanish",
      "sense": "Translations",
      "word": "la pregunta del millón"
    },
    {
      "code": "sv",
      "lang": "Swedish",
      "sense": "Translations",
      "tags": [
        "common-gender"
      ],
      "word": "tiotusenkronorsfråga"
    }
  ],
  "word": "million-dollar question"
}