"ABC book" meaning in English

{
  "forms": [
    {
      "form": "ABC books",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ABC book (plural ABC books)",
      "name": "en-noun"
    }
  ],
  "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": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Books",
          "orig": "en:Books",
          "parents": [
            "Literature",
            "Mass media",
            "Culture",
            "Entertainment",
            "Writing",
            "Media",
            "Society",
            "Human behaviour",
            "Language",
            "Communication",
            "All topics",
            "Human",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "Coordinate term: hornbook"
        }
      ],
      "glosses": [
        "A book that teaches the alphabet."
      ],
      "id": "en-ABC_book-en-noun-zfoQ5GNb",
      "links": [
        [
          "book",
          "book"
        ],
        [
          "alphabet",
          "alphabet"
        ]
      ],
      "synonyms": [
        {
          "word": "ABC"
        },
        {
          "word": "primer"
        }
      ]
    }
  ],
  "word": "ABC book"
}

{
  "forms": [
    {
      "form": "ABC books",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ABC book (plural ABC books)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Books"
      ],
      "examples": [
        {
          "text": "Coordinate term: hornbook"
        }
      ],
      "glosses": [
        "A book that teaches the alphabet."
      ],
      "links": [
        [
          "book",
          "book"
        ],
        [
          "alphabet",
          "alphabet"
        ]
      ],
      "synonyms": [
        {
          "word": "ABC"
        },
        {
          "word": "primer"
        }
      ]
    }
  ],
  "word": "ABC book"
}