".22" meaning in English

{
  "forms": [
    {
      "form": ".22s",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": ".22 (plural .22s)",
      "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": "Firearms",
          "orig": "en:Firearms",
          "parents": [
            "Weapons",
            "Hunting",
            "Military",
            "Tools",
            "Human activity",
            "Society",
            "Technology",
            "Human behaviour",
            "All topics",
            "Human",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2001, Chilco Choate, The Fire Still Burns: A Life of Trail Talk and Contrary Opinions, page 29:",
          "text": "I would rather have a .22 than an axe or a club, that's for sure",
          "type": "quote"
        }
      ],
      "glosses": [
        "A standard kind of firearm designed to fire bullets that are approximately 0.22 inch in diameter."
      ],
      "id": "en-.22-en-noun-bIXirDoh",
      "links": [
        [
          "firearm",
          "firearm"
        ]
      ],
      "raw_glosses": [
        "(firearms) A standard kind of firearm designed to fire bullets that are approximately 0.22 inch in diameter."
      ],
      "related": [
        {
          "word": ".38"
        },
        {
          "word": ".45"
        }
      ],
      "topics": [
        "engineering",
        "firearms",
        "government",
        "military",
        "natural-sciences",
        "physical-sciences",
        "politics",
        "tools",
        "war",
        "weaponry"
      ]
    }
  ],
  "word": ".22"
}

{
  "forms": [
    {
      "form": ".22s",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": ".22 (plural .22s)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": ".38"
    },
    {
      "word": ".45"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms spelled with .",
        "English terms spelled with numbers",
        "English terms with quotations",
        "English words without vowels",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Firearms"
      ],
      "examples": [
        {
          "ref": "2001, Chilco Choate, The Fire Still Burns: A Life of Trail Talk and Contrary Opinions, page 29:",
          "text": "I would rather have a .22 than an axe or a club, that's for sure",
          "type": "quote"
        }
      ],
      "glosses": [
        "A standard kind of firearm designed to fire bullets that are approximately 0.22 inch in diameter."
      ],
      "links": [
        [
          "firearm",
          "firearm"
        ]
      ],
      "raw_glosses": [
        "(firearms) A standard kind of firearm designed to fire bullets that are approximately 0.22 inch in diameter."
      ],
      "topics": [
        "engineering",
        "firearms",
        "government",
        "military",
        "natural-sciences",
        "physical-sciences",
        "politics",
        "tools",
        "war",
        "weaponry"
      ]
    }
  ],
  "word": ".22"
}