"místnostmi" meaning in Tchèque

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de noms communs en tchèque",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Tchèque",
      "orig": "tchèque",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Tchèque",
  "lang_code": "cs",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "form_of": [
        {
          "word": "místnost"
        }
      ],
      "glosses": [
        "Instrumental pluriel de místnost."
      ],
      "id": "fr-místnostmi-cs-noun-OYsRrg5R"
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "místnostmi"
}

{
  "categories": [
    "Formes de noms communs en tchèque",
    "tchèque"
  ],
  "lang": "Tchèque",
  "lang_code": "cs",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "form_of": [
        {
          "word": "místnost"
        }
      ],
      "glosses": [
        "Instrumental pluriel de místnost."
      ]
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "místnostmi"
}