"arch" meaning in Gallois

{
  "categories": [
    {
      "kind": "other",
      "name": "Mots en gallois issus d’un mot en latin",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms communs en gallois",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Gallois",
      "orig": "gallois",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "Du latin arca (« coffre ») ; comparer avec arc’h en breton, argh en cornique (sens identique)."
  ],
  "forms": [
    {
      "form": "eirch",
      "tags": [
        "plural",
        "unmutated"
      ]
    },
    {
      "form": "harch",
      "raw_tags": [
        "Prothèse h"
      ],
      "tags": [
        "singular"
      ]
    },
    {
      "form": "heirch",
      "raw_tags": [
        "Prothèse h"
      ],
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Gallois",
  "lang_code": "cy",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "glosses": [
        "Arche, coffre."
      ],
      "id": "fr-arch-cy-noun-o2Vn3RFB"
    },
    {
      "glosses": [
        "Cercueil."
      ],
      "id": "fr-arch-cy-noun-DLuZ5etF"
    }
  ],
  "sounds": [
    {
      "ipa": "\\aʁχ\\"
    }
  ],
  "tags": [
    "feminine"
  ],
  "word": "arch"
}

{
  "categories": [
    "Mots en gallois issus d’un mot en latin",
    "Noms communs en gallois",
    "gallois"
  ],
  "etymology_texts": [
    "Du latin arca (« coffre ») ; comparer avec arc’h en breton, argh en cornique (sens identique)."
  ],
  "forms": [
    {
      "form": "eirch",
      "tags": [
        "plural",
        "unmutated"
      ]
    },
    {
      "form": "harch",
      "raw_tags": [
        "Prothèse h"
      ],
      "tags": [
        "singular"
      ]
    },
    {
      "form": "heirch",
      "raw_tags": [
        "Prothèse h"
      ],
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Gallois",
  "lang_code": "cy",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "glosses": [
        "Arche, coffre."
      ]
    },
    {
      "glosses": [
        "Cercueil."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\aʁχ\\"
    }
  ],
  "tags": [
    "feminine"
  ],
  "word": "arch"
}