"blue hour" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "fr",
        "3": "heure bleue"
      },
      "expansion": "Calque of French heure bleue",
      "name": "calque"
    }
  ],
  "etymology_text": "Calque of French heure bleue.",
  "forms": [
    {
      "form": "blue hours",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "blue hour (plural blue hours)",
      "name": "en-noun"
    }
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
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        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Times of day",
          "orig": "en:Times of day",
          "parents": [
            "Periodic occurrences",
            "Timekeeping",
            "Time",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "Coordinate term: golden hour"
        }
      ],
      "glosses": [
        "The period of twilight when the Sun is approximately 4-8° below the horizon and the sky is within a range of blue colors."
      ],
      "id": "en-blue_hour-en-noun-u-xYUYQE",
      "links": [
        [
          "twilight",
          "twilight"
        ],
        [
          "blue",
          "blue"
        ]
      ],
      "synonyms": [
        {
          "word": "crepuscule"
        },
        {
          "word": "gloaming"
        },
        {
          "word": "twilight"
        }
      ],
      "translations": [
        {
          "code": "fr",
          "lang": "French",
          "sense": "period of twilight",
          "tags": [
            "feminine"
          ],
          "word": "heure bleue"
        },
        {
          "code": "de",
          "lang": "German",
          "sense": "period of twilight",
          "tags": [
            "feminine"
          ],
          "word": "blaue Stunde"
        },
        {
          "code": "ru",
          "lang": "Russian",
          "roman": "režímnoje vrémja",
          "sense": "period of twilight",
          "tags": [
            "neuter"
          ],
          "word": "режи́мное вре́мя"
        }
      ],
      "wikipedia": [
        "blue hour"
      ]
    }
  ],
  "word": "blue hour"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "fr",
        "3": "heure bleue"
      },
      "expansion": "Calque of French heure bleue",
      "name": "calque"
    }
  ],
  "etymology_text": "Calque of French heure bleue.",
  "forms": [
    {
      "form": "blue hours",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "blue hour (plural blue hours)",
      "name": "en-noun"
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
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        "en:Times of day"
      ],
      "examples": [
        {
          "text": "Coordinate term: golden hour"
        }
      ],
      "glosses": [
        "The period of twilight when the Sun is approximately 4-8° below the horizon and the sky is within a range of blue colors."
      ],
      "links": [
        [
          "twilight",
          "twilight"
        ],
        [
          "blue",
          "blue"
        ]
      ],
      "wikipedia": [
        "blue hour"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "crepuscule"
    },
    {
      "word": "gloaming"
    },
    {
      "word": "twilight"
    }
  ],
  "translations": [
    {
      "code": "fr",
      "lang": "French",
      "sense": "period of twilight",
      "tags": [
        "feminine"
      ],
      "word": "heure bleue"
    },
    {
      "code": "de",
      "lang": "German",
      "sense": "period of twilight",
      "tags": [
        "feminine"
      ],
      "word": "blaue Stunde"
    },
    {
      "code": "ru",
      "lang": "Russian",
      "roman": "režímnoje vrémja",
      "sense": "period of twilight",
      "tags": [
        "neuter"
      ],
      "word": "режи́мное вре́мя"
    }
  ],
  "word": "blue hour"
}