"ἡρώοιν" 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",
  "senses": [
    {
      "form_of": [
        {
          "word": "ἥρως"
        }
      ],
      "glosses": [
        "Génitif duel de ἥρως."
      ],
      "id": "fr-ἡρώοιν-grc-noun-Pv-F0xl1"
    },
    {
      "form_of": [
        {
          "word": "ἥρως"
        }
      ],
      "glosses": [
        "Datif duel de ἥρως."
      ],
      "id": "fr-ἡρώοιν-grc-noun-9~WJ9-v1"
    }
  ],
  "sounds": [
    {
      "ipa": "*\\hɛː.ˈrɔː.o͜ɪn\\"
    }
  ],
  "tags": [
    "form-of",
    "masculine"
  ],
  "word": "ἡρώοιν"
}

{
  "categories": [
    "Formes de noms communs en grec ancien",
    "grec ancien"
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "form_of": [
        {
          "word": "ἥρως"
        }
      ],
      "glosses": [
        "Génitif duel de ἥρως."
      ]
    },
    {
      "form_of": [
        {
          "word": "ἥρως"
        }
      ],
      "glosses": [
        "Datif duel de ἥρως."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\hɛː.ˈrɔː.o͜ɪn\\"
    }
  ],
  "tags": [
    "form-of",
    "masculine"
  ],
  "word": "ἡρώοιν"
}