"garbon" meaning in Breton

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de noms communs en breton",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Breton",
      "orig": "breton",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "karbon",
      "tags": [
        "unmutated"
      ]
    },
    {
      "form": "cʼharbon",
      "tags": [
        "mutation-spirant"
      ]
    }
  ],
  "lang": "Breton",
  "lang_code": "br",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "form_of": [
        {
          "word": "karbon"
        }
      ],
      "glosses": [
        "Forme mutée de karbon par adoucissement (k > g)."
      ],
      "id": "fr-garbon-br-noun-gUrWknap"
    }
  ],
  "sounds": [
    {
      "ipa": "\\ˈɡar.bɔ̃n\\"
    }
  ],
  "tags": [
    "form-of",
    "masculine"
  ],
  "word": "garbon"
}

{
  "categories": [
    "Formes de noms communs en breton",
    "breton"
  ],
  "forms": [
    {
      "form": "karbon",
      "tags": [
        "unmutated"
      ]
    },
    {
      "form": "cʼharbon",
      "tags": [
        "mutation-spirant"
      ]
    }
  ],
  "lang": "Breton",
  "lang_code": "br",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "form_of": [
        {
          "word": "karbon"
        }
      ],
      "glosses": [
        "Forme mutée de karbon par adoucissement (k > g)."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\ˈɡar.bɔ̃n\\"
    }
  ],
  "tags": [
    "form-of",
    "masculine"
  ],
  "word": "garbon"
}