"Mare Tranquillitatis" meaning in Conventions internationales

{
  "categories": [
    {
      "kind": "other",
      "name": "Noms propres en conventions internationales",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Toponymes de la Lune en conventions internationales",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Conventions internationales",
      "orig": "conventions internationales",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "(1651) Nommée par Francesco Grimaldi et Giovanni Battista Riccioli."
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "name",
  "pos_title": "Nom propre",
  "senses": [
    {
      "glosses": [
        "Mer de la Tranquillité (Lune)."
      ],
      "id": "fr-Mare_Tranquillitatis-conv-name-YE2yiqkr"
    }
  ],
  "word": "Mare Tranquillitatis"
}

{
  "categories": [
    "Noms propres en conventions internationales",
    "Toponymes de la Lune en conventions internationales",
    "conventions internationales"
  ],
  "etymology_texts": [
    "(1651) Nommée par Francesco Grimaldi et Giovanni Battista Riccioli."
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "name",
  "pos_title": "Nom propre",
  "senses": [
    {
      "glosses": [
        "Mer de la Tranquillité (Lune)."
      ]
    }
  ],
  "word": "Mare Tranquillitatis"
}