"γερουσιάρχης" meaning in Grec ancien

{
  "categories": [
    {
      "kind": "other",
      "name": "Compositions en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms communs en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Grec ancien",
      "orig": "grec ancien",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "lang": "Français",
      "lang_code": "fr",
      "word": "gérousiarque"
    },
    {
      "lang": "Latin",
      "lang_code": "la",
      "word": "gerusiarches"
    }
  ],
  "etymology_texts": [
    "Motcomposé de γερουσία, gerousía (« sénat ») et de ἄρχω, árkhô (« commander »)."
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    ":Modèle:grc-décl-nomm-1-ης-ου",
    "γερουσιάρχης, gerousiárkhês"
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Wiktionnaire:Exemples manquants en grec ancien",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Président du sénat."
      ],
      "id": "fr-γερουσιάρχης-grc-noun-TZj5d~nq"
    }
  ],
  "sounds": [
    {
      "ipa": "*\\ɡe.roː.si.ˈar.kʰɛːs\\"
    }
  ],
  "tags": [
    "masculine"
  ],
  "word": "γερουσιάρχης"
}

{
  "categories": [
    "Compositions en grec ancien",
    "Noms communs en grec ancien",
    "grec ancien"
  ],
  "derived": [
    {
      "lang": "Français",
      "lang_code": "fr",
      "word": "gérousiarque"
    },
    {
      "lang": "Latin",
      "lang_code": "la",
      "word": "gerusiarches"
    }
  ],
  "etymology_texts": [
    "Motcomposé de γερουσία, gerousía (« sénat ») et de ἄρχω, árkhô (« commander »)."
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    ":Modèle:grc-décl-nomm-1-ης-ου",
    "γερουσιάρχης, gerousiárkhês"
  ],
  "senses": [
    {
      "categories": [
        "Wiktionnaire:Exemples manquants en grec ancien"
      ],
      "glosses": [
        "Président du sénat."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\ɡe.roː.si.ˈar.kʰɛːs\\"
    }
  ],
  "tags": [
    "masculine"
  ],
  "word": "γερουσιάρχης"
}