"bo-" meaning in Gaulois

{
  "categories": [
    {
      "kind": "other",
      "name": "Animaux en gaulois",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Mots attestés en gaulois",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Mots en gaulois issus d’un mot en indo-européen commun",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Mots en gaulois issus d’un mot en proto-celtique",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms communs en gaulois",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Gaulois",
      "orig": "gaulois",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Étymologies en gaulois incluant une reconstruction",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "word": "boustom"
    }
  ],
  "etymology_texts": [
    "Du proto-celtique *bow-, provient de l’indo-européen commun *gʷōw-."
  ],
  "lang": "Gaulois",
  "lang_code": "gaulois",
  "pos": "noun",
  "pos_title": "Nom commun",
  "related": [
    {
      "word": "bou-"
    }
  ],
  "senses": [
    {
      "glosses": [
        "Vache, bœuf."
      ],
      "id": "fr-bo--gaulois-noun-JoxHCy0S"
    }
  ],
  "word": "bo-"
}

{
  "categories": [
    "Animaux en gaulois",
    "Mots attestés en gaulois",
    "Mots en gaulois issus d’un mot en indo-européen commun",
    "Mots en gaulois issus d’un mot en proto-celtique",
    "Noms communs en gaulois",
    "gaulois",
    "Étymologies en gaulois incluant une reconstruction"
  ],
  "derived": [
    {
      "word": "boustom"
    }
  ],
  "etymology_texts": [
    "Du proto-celtique *bow-, provient de l’indo-européen commun *gʷōw-."
  ],
  "lang": "Gaulois",
  "lang_code": "gaulois",
  "pos": "noun",
  "pos_title": "Nom commun",
  "related": [
    {
      "word": "bou-"
    }
  ],
  "senses": [
    {
      "glosses": [
        "Vache, bœuf."
      ]
    }
  ],
  "word": "bo-"
}