"nache" meaning in Ancien français

{
  "categories": [
    {
      "kind": "other",
      "name": "Ancien français",
      "orig": "ancien français",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "word": "nacherel"
    },
    {
      "translation": "fessu",
      "word": "nachu"
    }
  ],
  "etymology_texts": [
    "Du latin natis."
  ],
  "forms": [
    {
      "form": "naches",
      "raw_tags": [
        "Cas sujet"
      ],
      "tags": [
        "plural"
      ]
    },
    {
      "form": "naches",
      "raw_tags": [
        "Cas régime"
      ],
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Ancien français",
  "lang_code": "fro",
  "pos": "noun",
  "pos_title": "Nom commun",
  "related": [
    {
      "word": "naiche"
    },
    {
      "word": "naige"
    },
    {
      "word": "nasche"
    },
    {
      "word": "nace"
    },
    {
      "word": "nage"
    },
    {
      "word": "natege"
    }
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en ancien français de l’anatomie",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Fesse."
      ],
      "id": "fr-nache-fro-noun-l6pAzIf2",
      "topics": [
        "anatomy"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\na.tʃə\\"
    }
  ],
  "tags": [
    "feminine"
  ],
  "word": "nache"
}

{
  "categories": [
    "ancien français"
  ],
  "derived": [
    {
      "word": "nacherel"
    },
    {
      "translation": "fessu",
      "word": "nachu"
    }
  ],
  "etymology_texts": [
    "Du latin natis."
  ],
  "forms": [
    {
      "form": "naches",
      "raw_tags": [
        "Cas sujet"
      ],
      "tags": [
        "plural"
      ]
    },
    {
      "form": "naches",
      "raw_tags": [
        "Cas régime"
      ],
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Ancien français",
  "lang_code": "fro",
  "pos": "noun",
  "pos_title": "Nom commun",
  "related": [
    {
      "word": "naiche"
    },
    {
      "word": "naige"
    },
    {
      "word": "nasche"
    },
    {
      "word": "nace"
    },
    {
      "word": "nage"
    },
    {
      "word": "natege"
    }
  ],
  "senses": [
    {
      "categories": [
        "Lexique en ancien français de l’anatomie"
      ],
      "glosses": [
        "Fesse."
      ],
      "topics": [
        "anatomy"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\na.tʃə\\"
    }
  ],
  "tags": [
    "feminine"
  ],
  "word": "nache"
}