"canine letter" meaning in English

{
  "etymology_text": "So called because it sometimes represents a sound like a dog's growl.",
  "forms": [
    {
      "form": "the canine letter",
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "the canine letter"
      },
      "expansion": "the canine letter",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Latin letter names",
          "orig": "en:Latin letter names",
          "parents": [
            "Letter names",
            "Letters, symbols, and punctuation",
            "Names",
            "Orthography",
            "All topics",
            "Proper nouns",
            "Terms by semantic function",
            "Writing",
            "Fundamental",
            "Nouns",
            "Human behaviour",
            "Language",
            "Lemmas",
            "Human",
            "Communication"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1833, Thomas Keightley, Fairy Mythology, volume I, London: William Harrison Ainsworth, page 10",
          "text": "All the foregoing etymologies, be it observed, are the conjectures of English scholars; for the English is the only language in which the name of the individual, Fairy, has the canine letter to afford any foundation for them.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The letter r."
      ],
      "id": "en-canine_letter-en-noun-mfvbB5DI",
      "links": [
        [
          "r",
          "r"
        ]
      ],
      "raw_glosses": [
        "(archaic) The letter r."
      ],
      "tags": [
        "archaic"
      ]
    }
  ],
  "word": "canine letter"
}

{
  "etymology_text": "So called because it sometimes represents a sound like a dog's growl.",
  "forms": [
    {
      "form": "the canine letter",
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "the canine letter"
      },
      "expansion": "the canine letter",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with archaic senses",
        "English terms with quotations",
        "en:Latin letter names"
      ],
      "examples": [
        {
          "ref": "1833, Thomas Keightley, Fairy Mythology, volume I, London: William Harrison Ainsworth, page 10",
          "text": "All the foregoing etymologies, be it observed, are the conjectures of English scholars; for the English is the only language in which the name of the individual, Fairy, has the canine letter to afford any foundation for them.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The letter r."
      ],
      "links": [
        [
          "r",
          "r"
        ]
      ],
      "raw_glosses": [
        "(archaic) The letter r."
      ],
      "tags": [
        "archaic"
      ]
    }
  ],
  "word": "canine letter"
}