"check digit" meaning in English

{
  "forms": [
    {
      "form": "check digits",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "checkdigit",
      "tags": [
        "alternative"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "check digit (plural check digits)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Mandarin translations",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              35,
              46
            ]
          ],
          "text": "The last digit of the barcode is a check digit, calculated from the others.",
          "type": "example"
        }
      ],
      "glosses": [
        "A single-digit checksum."
      ],
      "id": "en-check_digit-en-noun-Ima2xrzG",
      "links": [
        [
          "digit",
          "digit"
        ],
        [
          "checksum",
          "checksum"
        ]
      ],
      "translations": [
        {
          "code": "cmn",
          "lang": "Chinese Mandarin",
          "lang_code": "cmn",
          "roman": "jiàoyànmǎ",
          "sense": "Translations",
          "word": "校驗碼 /校验码"
        },
        {
          "code": "cmn",
          "lang": "Chinese Mandarin",
          "lang_code": "cmn",
          "sense": "Translations",
          "word": "檢核碼 /检核码"
        }
      ]
    }
  ],
  "word": "check digit"
}

{
  "forms": [
    {
      "form": "check digits",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "checkdigit",
      "tags": [
        "alternative"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "check digit (plural check digits)",
      "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",
        "English terms with usage examples",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Mandarin translations",
        "Translation table header lacks gloss"
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              35,
              46
            ]
          ],
          "text": "The last digit of the barcode is a check digit, calculated from the others.",
          "type": "example"
        }
      ],
      "glosses": [
        "A single-digit checksum."
      ],
      "links": [
        [
          "digit",
          "digit"
        ],
        [
          "checksum",
          "checksum"
        ]
      ]
    }
  ],
  "translations": [
    {
      "code": "cmn",
      "lang": "Chinese Mandarin",
      "lang_code": "cmn",
      "roman": "jiàoyànmǎ",
      "sense": "Translations",
      "word": "校驗碼 /校验码"
    },
    {
      "code": "cmn",
      "lang": "Chinese Mandarin",
      "lang_code": "cmn",
      "sense": "Translations",
      "word": "檢核碼 /检核码"
    }
  ],
  "word": "check digit"
}