"ξύν" meaning in Grec ancien

{
  "categories": [
    {
      "kind": "other",
      "name": "Prépositions en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Grec ancien",
      "orig": "grec ancien",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "prep",
  "pos_title": "Préposition",
  "raw_tags": [
    "ξύν, xún"
  ],
  "senses": [
    {
      "alt_of": [
        {
          "word": "σύν"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Wiktionnaire:Exemples manquants en grec ancien",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Variante de σύν."
      ],
      "id": "fr-ξύν-grc-prep-PFwrPbak",
      "tags": [
        "alt-of"
      ]
    }
  ],
  "word": "ξύν"
}

{
  "categories": [
    "Prépositions en grec ancien",
    "grec ancien"
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "prep",
  "pos_title": "Préposition",
  "raw_tags": [
    "ξύν, xún"
  ],
  "senses": [
    {
      "alt_of": [
        {
          "word": "σύν"
        }
      ],
      "categories": [
        "Wiktionnaire:Exemples manquants en grec ancien"
      ],
      "glosses": [
        "Variante de σύν."
      ],
      "tags": [
        "alt-of"
      ]
    }
  ],
  "word": "ξύν"
}