"closed compound" meaning in English

{
  "forms": [
    {
      "form": "closed compounds",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "closed compound (plural closed compounds)",
      "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"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Grammar",
          "orig": "en:Grammar",
          "parents": [
            "Linguistics",
            "Language",
            "Social sciences",
            "Communication",
            "Sciences",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "coordinate_terms": [
        {
          "word": "open compound"
        }
      ],
      "glosses": [
        "A compound word without spaces in it."
      ],
      "hypernyms": [
        {
          "word": "compound"
        },
        {
          "word": "compound word"
        }
      ],
      "id": "en-closed_compound-en-noun-pVTUgSZT",
      "links": [
        [
          "grammar",
          "grammar"
        ],
        [
          "compound word",
          "compound word"
        ],
        [
          "space",
          "space"
        ]
      ],
      "raw_glosses": [
        "(grammar) A compound word without spaces in it."
      ],
      "synonyms": [
        {
          "word": "solid compound"
        }
      ],
      "topics": [
        "grammar",
        "human-sciences",
        "linguistics",
        "sciences"
      ],
      "translations": [
        {
          "code": "fi",
          "lang": "Finnish",
          "note": "in Finnish, but not in English, all compounds are written without spaces; see open compound",
          "sense": "grammar: compound without spaces",
          "word": "(yhteenkirjoitettu) yhdyssana"
        },
        {
          "code": "hu",
          "lang": "Hungarian",
          "sense": "grammar: compound without spaces",
          "word": "egybeírt összetétel"
        }
      ]
    }
  ],
  "word": "closed compound"
}

{
  "coordinate_terms": [
    {
      "word": "open compound"
    }
  ],
  "forms": [
    {
      "form": "closed compounds",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "closed compound (plural closed compounds)",
      "name": "en-noun"
    }
  ],
  "hypernyms": [
    {
      "word": "compound"
    },
    {
      "word": "compound word"
    }
  ],
  "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",
        "en:Grammar"
      ],
      "glosses": [
        "A compound word without spaces in it."
      ],
      "links": [
        [
          "grammar",
          "grammar"
        ],
        [
          "compound word",
          "compound word"
        ],
        [
          "space",
          "space"
        ]
      ],
      "raw_glosses": [
        "(grammar) A compound word without spaces in it."
      ],
      "topics": [
        "grammar",
        "human-sciences",
        "linguistics",
        "sciences"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "solid compound"
    }
  ],
  "translations": [
    {
      "code": "fi",
      "lang": "Finnish",
      "note": "in Finnish, but not in English, all compounds are written without spaces; see open compound",
      "sense": "grammar: compound without spaces",
      "word": "(yhteenkirjoitettu) yhdyssana"
    },
    {
      "code": "hu",
      "lang": "Hungarian",
      "sense": "grammar: compound without spaces",
      "word": "egybeírt összetétel"
    }
  ],
  "word": "closed compound"
}