"οὐδέν" meaning in Grec ancien

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de pronoms en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Grec ancien",
      "orig": "grec ancien",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "pron",
  "pos_title": "Forme de pronom",
  "raw_tags": [
    "οὐδέν, oudén"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "οὐδείς"
        }
      ],
      "glosses": [
        "Nominatif neutre singulier de οὐδείς."
      ],
      "id": "fr-οὐδέν-grc-pron-jHClTCdG"
    },
    {
      "form_of": [
        {
          "word": "οὐδείς"
        }
      ],
      "glosses": [
        "Vocatif neutre singulier de οὐδείς."
      ],
      "id": "fr-οὐδέν-grc-pron--8UgNwI6"
    },
    {
      "form_of": [
        {
          "word": "οὐδείς"
        }
      ],
      "glosses": [
        "Accusatif neutre singulier de οὐδείς."
      ],
      "id": "fr-οὐδέν-grc-pron-0dhjSXm~"
    }
  ],
  "sounds": [
    {
      "ipa": "*\\oː.dén\\"
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "οὐδέν"
}

{
  "categories": [
    "Formes de pronoms en grec ancien",
    "grec ancien"
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "pron",
  "pos_title": "Forme de pronom",
  "raw_tags": [
    "οὐδέν, oudén"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "οὐδείς"
        }
      ],
      "glosses": [
        "Nominatif neutre singulier de οὐδείς."
      ]
    },
    {
      "form_of": [
        {
          "word": "οὐδείς"
        }
      ],
      "glosses": [
        "Vocatif neutre singulier de οὐδείς."
      ]
    },
    {
      "form_of": [
        {
          "word": "οὐδείς"
        }
      ],
      "glosses": [
        "Accusatif neutre singulier de οὐδείς."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\oː.dén\\"
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "οὐδέν"
}