"XX" meaning in Conventions internationales

{
  "categories": [
    {
      "kind": "other",
      "name": "Nombres en chiffres romains",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Palindromes en conventions internationales",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Symboles en conventions internationales",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Conventions internationales",
      "orig": "conventions internationales",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "symbol",
  "pos_title": "Symbole",
  "related": [
    {
      "sense": "mâle",
      "word": "XY"
    },
    {
      "sense": "mâle",
      "word": "X0"
    }
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en conventions internationales de la biologie",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Femelle ayant deux chromosomes X, faisant partie des systèmes de détermination sexuelle XY et X0."
      ],
      "id": "fr-XX-conv-symbol-JKa3VrNH",
      "topics": [
        "biology"
      ]
    }
  ],
  "word": "XX"
}

{
  "categories": [
    {
      "kind": "other",
      "name": "Nombres en chiffres romains",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Numéraux",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Palindromes en conventions internationales",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Conventions internationales",
      "orig": "conventions internationales",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "num",
  "pos_title": "Numéral",
  "senses": [
    {
      "glosses": [
        "20 en chiffres romains majuscules."
      ],
      "id": "fr-XX-conv-num-TkhdK6yq"
    }
  ],
  "word": "XX"
}

{
  "categories": [
    "Nombres en chiffres romains",
    "Palindromes en conventions internationales",
    "Symboles en conventions internationales",
    "conventions internationales"
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "symbol",
  "pos_title": "Symbole",
  "related": [
    {
      "sense": "mâle",
      "word": "XY"
    },
    {
      "sense": "mâle",
      "word": "X0"
    }
  ],
  "senses": [
    {
      "categories": [
        "Lexique en conventions internationales de la biologie"
      ],
      "glosses": [
        "Femelle ayant deux chromosomes X, faisant partie des systèmes de détermination sexuelle XY et X0."
      ],
      "topics": [
        "biology"
      ]
    }
  ],
  "word": "XX"
}

{
  "categories": [
    "Nombres en chiffres romains",
    "Numéraux",
    "Palindromes en conventions internationales",
    "conventions internationales"
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "num",
  "pos_title": "Numéral",
  "senses": [
    {
      "glosses": [
        "20 en chiffres romains majuscules."
      ]
    }
  ],
  "word": "XX"
}