"boot block" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "boot",
        "3": "block"
      },
      "expansion": "boot + block",
      "name": "compound"
    }
  ],
  "etymology_text": "boot + block",
  "forms": [
    {
      "form": "boot blocks",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "boot block (plural boot blocks)",
      "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": "topical",
          "langcode": "en",
          "name": "Computing",
          "orig": "en:Computing",
          "parents": [
            "Technology",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A dedicated block usually at the beginning (first block on first track) of a storage medium that holds special data used to start a system. Some systems use a boot block of several physical sectors, while some use only one boot sector. Other manufacturers use the terms boot block and boot sector interchangeably."
      ],
      "id": "en-boot_block-en-noun-Gkflg8ms",
      "links": [
        [
          "computing",
          "computing#Noun"
        ],
        [
          "block",
          "block"
        ]
      ],
      "raw_glosses": [
        "(computing) A dedicated block usually at the beginning (first block on first track) of a storage medium that holds special data used to start a system. Some systems use a boot block of several physical sectors, while some use only one boot sector. Other manufacturers use the terms boot block and boot sector interchangeably."
      ],
      "related": [
        {
          "word": "block"
        },
        {
          "word": "MBR"
        },
        {
          "word": "sector"
        }
      ],
      "synonyms": [
        {
          "word": "boot sector"
        },
        {
          "word": "bootblock"
        }
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ],
      "translations": [
        {
          "code": "cmn",
          "lang": "Chinese Mandarin",
          "sense": "first block to start a system",
          "word": "啟動塊"
        },
        {
          "code": "cmn",
          "lang": "Chinese Mandarin",
          "roman": "qǐdòngkuài",
          "sense": "first block to start a system",
          "word": "启动块"
        },
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "first block to start a system",
          "word": "käynnistyslohko"
        }
      ]
    }
  ],
  "word": "boot block"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "boot",
        "3": "block"
      },
      "expansion": "boot + block",
      "name": "compound"
    }
  ],
  "etymology_text": "boot + block",
  "forms": [
    {
      "form": "boot blocks",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "boot block (plural boot blocks)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "block"
    },
    {
      "word": "MBR"
    },
    {
      "word": "sector"
    }
  ],
  "senses": [
    {
      "categories": [
        "English compound terms",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Computing"
      ],
      "glosses": [
        "A dedicated block usually at the beginning (first block on first track) of a storage medium that holds special data used to start a system. Some systems use a boot block of several physical sectors, while some use only one boot sector. Other manufacturers use the terms boot block and boot sector interchangeably."
      ],
      "links": [
        [
          "computing",
          "computing#Noun"
        ],
        [
          "block",
          "block"
        ]
      ],
      "raw_glosses": [
        "(computing) A dedicated block usually at the beginning (first block on first track) of a storage medium that holds special data used to start a system. Some systems use a boot block of several physical sectors, while some use only one boot sector. Other manufacturers use the terms boot block and boot sector interchangeably."
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "boot sector"
    },
    {
      "word": "bootblock"
    }
  ],
  "translations": [
    {
      "code": "cmn",
      "lang": "Chinese Mandarin",
      "sense": "first block to start a system",
      "word": "啟動塊"
    },
    {
      "code": "cmn",
      "lang": "Chinese Mandarin",
      "roman": "qǐdòngkuài",
      "sense": "first block to start a system",
      "word": "启动块"
    },
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "first block to start a system",
      "word": "käynnistyslohko"
    }
  ],
  "word": "boot block"
}