"letra" meaning in Basque

{
  "categories": [
    {
      "kind": "other",
      "name": "Mots en basque issus d’un mot en espagnol",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Mots en basque issus d’un mot en occitan",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms communs en basque",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Basque",
      "orig": "basque",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "translation": "illettré",
      "word": "letragabe"
    }
  ],
  "etymology_texts": [
    "De l’espagnol letra ou de l’occitan letra."
  ],
  "forms": [
    {
      "form": "Déclinaison"
    }
  ],
  "lang": "Basque",
  "lang_code": "eu",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Exemples en basque",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Lexique en basque de la typographie",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "frantses alfabetoko 26 letrak.",
          "translation": "les 26 lettres de l’alphabet français."
        }
      ],
      "glosses": [
        "Lettre."
      ],
      "id": "fr-letra-eu-noun-wvpjN0sF",
      "topics": [
        "typography"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "hizki"
    }
  ],
  "word": "letra"
}

{
  "categories": [
    "Mots en basque issus d’un mot en espagnol",
    "Mots en basque issus d’un mot en occitan",
    "Noms communs en basque",
    "basque"
  ],
  "derived": [
    {
      "translation": "illettré",
      "word": "letragabe"
    }
  ],
  "etymology_texts": [
    "De l’espagnol letra ou de l’occitan letra."
  ],
  "forms": [
    {
      "form": "Déclinaison"
    }
  ],
  "lang": "Basque",
  "lang_code": "eu",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "categories": [
        "Exemples en basque",
        "Lexique en basque de la typographie"
      ],
      "examples": [
        {
          "text": "frantses alfabetoko 26 letrak.",
          "translation": "les 26 lettres de l’alphabet français."
        }
      ],
      "glosses": [
        "Lettre."
      ],
      "topics": [
        "typography"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "hizki"
    }
  ],
  "word": "letra"
}