"Πειραιεῦ" meaning in Grec ancien

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de noms propres en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Grec ancien",
      "orig": "grec ancien",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "name",
  "pos_title": "Forme de nom propre",
  "raw_tags": [
    "Πειραιεῦ, Peiraieû"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "Πειραιεύς"
        }
      ],
      "glosses": [
        "Vocatif de Πειραιεύς."
      ],
      "id": "fr-Πειραιεῦ-grc-name-U0JLNrjZ"
    }
  ],
  "sounds": [
    {
      "ipa": "*\\peː.rai̯.êu̯\\"
    }
  ],
  "tags": [
    "form-of",
    "masculine"
  ],
  "word": "Πειραιεῦ"
}

{
  "categories": [
    "Formes de noms propres en grec ancien",
    "grec ancien"
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "name",
  "pos_title": "Forme de nom propre",
  "raw_tags": [
    "Πειραιεῦ, Peiraieû"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "Πειραιεύς"
        }
      ],
      "glosses": [
        "Vocatif de Πειραιεύς."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\peː.rai̯.êu̯\\"
    }
  ],
  "tags": [
    "form-of",
    "masculine"
  ],
  "word": "Πειραιεῦ"
}