"Big Red One" meaning in English

{
  "etymology_text": "The shoulder insignia of this unit is emblazoned with a red numeral one.",
  "forms": [
    {
      "form": "the Big Red One",
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "def": "1",
        "head": "Big Red One"
      },
      "expansion": "the Big Red One",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "American English",
          "parents": [],
          "source": "w"
        },
        {
          "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": "History of the United States",
          "orig": "en:History of the United States",
          "parents": [
            "United States",
            "History",
            "Countries",
            "Countries in North America",
            "All topics",
            "Polities",
            "Places",
            "North America",
            "Fundamental",
            "Names",
            "America",
            "Proper nouns",
            "Terms by semantic function",
            "Earth",
            "Nouns",
            "Nature",
            "Lemmas"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Military",
          "orig": "en:Military",
          "parents": [
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "One",
          "orig": "en:One",
          "parents": [
            "Numbers",
            "All topics",
            "Terms by semantic function",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "World War I",
          "orig": "en:World War I",
          "parents": [
            "Historical events",
            "History of Europe",
            "War",
            "History",
            "Europe",
            "Conflict",
            "Military",
            "Violence",
            "All topics",
            "Earth",
            "Eurasia",
            "Human behaviour",
            "Society",
            "Fundamental",
            "Nature",
            "Human"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "The United States 1st Infantry Division."
      ],
      "id": "en-Big_Red_One-en-name-zUUJW1gd",
      "raw_glosses": [
        "(US, informal) The United States 1st Infantry Division."
      ],
      "tags": [
        "US",
        "informal"
      ]
    }
  ],
  "word": "Big Red One"
}

{
  "etymology_text": "The shoulder insignia of this unit is emblazoned with a red numeral one.",
  "forms": [
    {
      "form": "the Big Red One",
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "def": "1",
        "head": "Big Red One"
      },
      "expansion": "the Big Red One",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "categories": [
        "American English",
        "English entries with incorrect language header",
        "English informal terms",
        "English lemmas",
        "English multiword terms",
        "English proper nouns",
        "English uncountable nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:History of the United States",
        "en:Military",
        "en:One",
        "en:World War I"
      ],
      "glosses": [
        "The United States 1st Infantry Division."
      ],
      "raw_glosses": [
        "(US, informal) The United States 1st Infantry Division."
      ],
      "tags": [
        "US",
        "informal"
      ]
    }
  ],
  "word": "Big Red One"
}