"groes" meaning in Gallois

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de noms communs en gallois",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Gallois",
      "orig": "gallois",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Gallois",
  "lang_code": "cy",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Wiktionnaire:Exemples manquants en gallois",
          "parents": [],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "word": "croes"
        }
      ],
      "glosses": [
        "Forme mutée de croes par adoucissement."
      ],
      "id": "fr-groes-cy-noun-XRhIojV9"
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "groes"
}

{
  "categories": [
    "Formes de noms communs en gallois",
    "gallois"
  ],
  "lang": "Gallois",
  "lang_code": "cy",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "categories": [
        "Wiktionnaire:Exemples manquants en gallois"
      ],
      "form_of": [
        {
          "word": "croes"
        }
      ],
      "glosses": [
        "Forme mutée de croes par adoucissement."
      ]
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "groes"
}