"γαστέροιν" meaning in Grec ancien

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de noms communs en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Grec ancien",
      "orig": "grec ancien",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "raw_tags": [
    "γαστέροιν, gastéroin"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "γαστήρ"
        }
      ],
      "glosses": [
        "Génitif duel de γαστήρ."
      ],
      "id": "fr-γαστέροιν-grc-noun-fzItrFF4"
    },
    {
      "form_of": [
        {
          "word": "γαστήρ"
        }
      ],
      "glosses": [
        "Datif duel de γαστήρ."
      ],
      "id": "fr-γαστέροιν-grc-noun-IYNBceDu"
    }
  ],
  "sounds": [
    {
      "ipa": "*\\ɡas.ˈte.ro͜ɪn\\"
    }
  ],
  "tags": [
    "feminine",
    "form-of"
  ],
  "word": "γαστέροιν"
}

{
  "categories": [
    "Formes de noms communs en grec ancien",
    "grec ancien"
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "raw_tags": [
    "γαστέροιν, gastéroin"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "γαστήρ"
        }
      ],
      "glosses": [
        "Génitif duel de γαστήρ."
      ]
    },
    {
      "form_of": [
        {
          "word": "γαστήρ"
        }
      ],
      "glosses": [
        "Datif duel de γαστήρ."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\ɡas.ˈte.ro͜ɪn\\"
    }
  ],
  "tags": [
    "feminine",
    "form-of"
  ],
  "word": "γαστέροιν"
}