"muren" meaning in Breton

{
  "categories": [
    {
      "kind": "other",
      "name": "Dates manquantes en breton",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Mots en breton issus d’un mot en ancien français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Mots en breton issus d’un mot en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Mots en breton issus d’un mot en latin",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms communs en breton",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Breton",
      "orig": "breton",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "(Date à préciser) De l'ancien français moreine, issu du latin muraena (« anguille, lamproie »), lui-même issu du grec ancien σμύραινα (« anguille »)."
  ],
  "lang": "Breton",
  "lang_code": "br",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Poissons en breton",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Murène."
      ],
      "id": "fr-muren-br-noun-mZ2Mxy7B",
      "topics": [
        "ichthyology"
      ]
    }
  ],
  "word": "muren"
}

{
  "categories": [
    "Dates manquantes en breton",
    "Mots en breton issus d’un mot en ancien français",
    "Mots en breton issus d’un mot en grec ancien",
    "Mots en breton issus d’un mot en latin",
    "Noms communs en breton",
    "breton"
  ],
  "etymology_texts": [
    "(Date à préciser) De l'ancien français moreine, issu du latin muraena (« anguille, lamproie »), lui-même issu du grec ancien σμύραινα (« anguille »)."
  ],
  "lang": "Breton",
  "lang_code": "br",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "categories": [
        "Poissons en breton"
      ],
      "glosses": [
        "Murène."
      ],
      "topics": [
        "ichthyology"
      ]
    }
  ],
  "word": "muren"
}