"灰色文獻" meaning in Chinese

{
  "forms": [
    {
      "form": "灰色文献",
      "raw_tags": [
        "Simplified Chinese"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "zh",
        "2": "noun"
      },
      "expansion": "灰色文獻",
      "name": "head"
    }
  ],
  "lang": "Chinese",
  "lang_code": "zh",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Chinese entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "zh",
          "name": "Sciences",
          "orig": "zh:Sciences",
          "parents": [
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "grey literature"
      ],
      "id": "en-灰色文獻-zh-noun-fCEuJ6cD",
      "links": [
        [
          "grey literature",
          "grey literature"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "tags": [
        "Mandarin",
        "Pinyin"
      ],
      "zh-pron": "huīsè wénxiàn"
    },
    {
      "tags": [
        "Mandarin",
        "bopomofo"
      ],
      "zh-pron": "ㄏㄨㄟ ㄙㄜˋ ㄨㄣˊ ㄒㄧㄢˋ"
    },
    {
      "tags": [
        "Hanyu-Pinyin",
        "Mandarin"
      ],
      "zh-pron": "huīsè wénxiàn"
    },
    {
      "tags": [
        "Mandarin",
        "Tongyong-Pinyin"
      ],
      "zh-pron": "hueisè wúnsiàn"
    },
    {
      "tags": [
        "Mandarin",
        "Wade-Giles"
      ],
      "zh-pron": "hui¹-sê⁴ wên²-hsien⁴"
    },
    {
      "tags": [
        "Mandarin",
        "Yale"
      ],
      "zh-pron": "hwēi-sè wén-syàn"
    },
    {
      "tags": [
        "Gwoyeu-Romatsyh",
        "Mandarin"
      ],
      "zh-pron": "hueiseh wenshiann"
    },
    {
      "tags": [
        "Mandarin",
        "Palladius"
      ],
      "zh-pron": "хуэйсэ вэньсянь"
    },
    {
      "tags": [
        "Mandarin",
        "Palladius"
      ],
      "zh-pron": "xuejsɛ vɛnʹsjanʹ"
    },
    {
      "ipa": "/xu̯eɪ̯⁵⁵ sɤ⁵¹ wən³⁵ ɕi̯ɛn⁵¹/",
      "tags": [
        "Mandarin",
        "Sinological-IPA"
      ]
    },
    {
      "ipa": "/xu̯eɪ̯⁵⁵ sɤ⁵¹ wən³⁵ ɕi̯ɛn⁵¹/"
    }
  ],
  "word": "灰色文獻"
}

{
  "forms": [
    {
      "form": "灰色文献",
      "raw_tags": [
        "Simplified Chinese"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "zh",
        "2": "noun"
      },
      "expansion": "灰色文獻",
      "name": "head"
    }
  ],
  "lang": "Chinese",
  "lang_code": "zh",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Chinese entries with incorrect language header",
        "Chinese lemmas",
        "Chinese nouns",
        "Chinese terms spelled with 文",
        "Chinese terms spelled with 灰",
        "Chinese terms spelled with 獻",
        "Chinese terms spelled with 色",
        "Chinese terms with IPA pronunciation",
        "Mandarin lemmas",
        "Mandarin nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "zh:Sciences"
      ],
      "glosses": [
        "grey literature"
      ],
      "links": [
        [
          "grey literature",
          "grey literature"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "tags": [
        "Mandarin",
        "Pinyin"
      ],
      "zh-pron": "huīsè wénxiàn"
    },
    {
      "tags": [
        "Mandarin",
        "bopomofo"
      ],
      "zh-pron": "ㄏㄨㄟ ㄙㄜˋ ㄨㄣˊ ㄒㄧㄢˋ"
    },
    {
      "tags": [
        "Hanyu-Pinyin",
        "Mandarin"
      ],
      "zh-pron": "huīsè wénxiàn"
    },
    {
      "tags": [
        "Mandarin",
        "Tongyong-Pinyin"
      ],
      "zh-pron": "hueisè wúnsiàn"
    },
    {
      "tags": [
        "Mandarin",
        "Wade-Giles"
      ],
      "zh-pron": "hui¹-sê⁴ wên²-hsien⁴"
    },
    {
      "tags": [
        "Mandarin",
        "Yale"
      ],
      "zh-pron": "hwēi-sè wén-syàn"
    },
    {
      "tags": [
        "Gwoyeu-Romatsyh",
        "Mandarin"
      ],
      "zh-pron": "hueiseh wenshiann"
    },
    {
      "tags": [
        "Mandarin",
        "Palladius"
      ],
      "zh-pron": "хуэйсэ вэньсянь"
    },
    {
      "tags": [
        "Mandarin",
        "Palladius"
      ],
      "zh-pron": "xuejsɛ vɛnʹsjanʹ"
    },
    {
      "ipa": "/xu̯eɪ̯⁵⁵ sɤ⁵¹ wən³⁵ ɕi̯ɛn⁵¹/",
      "tags": [
        "Mandarin",
        "Sinological-IPA"
      ]
    },
    {
      "ipa": "/xu̯eɪ̯⁵⁵ sɤ⁵¹ wən³⁵ ɕi̯ɛn⁵¹/"
    }
  ],
  "word": "灰色文獻"
}