"arm span" meaning in English

{
  "forms": [
    {
      "form": "arm spans",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "armspan",
      "tags": [
        "alternative"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "arm span (plural arm spans)",
      "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"
        }
      ],
      "glosses": [
        "The length of a person's outstretched arms, measured from the fingertips of the two middle fingers. See also fathom"
      ],
      "id": "en-arm_span-en-noun-MAGF-aKz",
      "links": [
        [
          "middle finger",
          "middle finger"
        ],
        [
          "fathom#Noun",
          "fathom#Noun"
        ]
      ],
      "synonyms": [
        {
          "word": "wingspan"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈɑɹm.spæn/",
      "tags": [
        "US"
      ]
    }
  ],
  "word": "arm span"
}

{
  "forms": [
    {
      "form": "arm spans",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "armspan",
      "tags": [
        "alternative"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "arm span (plural arm spans)",
      "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"
      ],
      "glosses": [
        "The length of a person's outstretched arms, measured from the fingertips of the two middle fingers. See also fathom"
      ],
      "links": [
        [
          "middle finger",
          "middle finger"
        ],
        [
          "fathom#Noun",
          "fathom#Noun"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈɑɹm.spæn/",
      "tags": [
        "US"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "wingspan"
    }
  ],
  "word": "arm span"
}