"stadia hair" meaning in English

{
  "forms": [
    {
      "form": "stadia hairs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "stadia hair (plural stadia hairs)",
      "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": "Surveying",
          "orig": "en:Surveying",
          "parents": [
            "Geography",
            "Earth sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "In a theodolite, etc., one of the horizontal crosshairs equidistant from the central horizontal crosshair."
      ],
      "id": "en-stadia_hair-en-noun-ba-v~YFm",
      "links": [
        [
          "surveying",
          "surveying#Noun"
        ],
        [
          "theodolite",
          "theodolite"
        ],
        [
          "horizontal",
          "horizontal"
        ],
        [
          "crosshair",
          "crosshair"
        ],
        [
          "equidistant",
          "equidistant"
        ]
      ],
      "raw_glosses": [
        "(surveying) In a theodolite, etc., one of the horizontal crosshairs equidistant from the central horizontal crosshair."
      ],
      "synonyms": [
        {
          "word": "stadia wire"
        }
      ],
      "topics": [
        "geography",
        "natural-sciences",
        "surveying"
      ]
    }
  ],
  "word": "stadia hair"
}

{
  "forms": [
    {
      "form": "stadia hairs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "stadia hair (plural stadia hairs)",
      "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",
        "en:Surveying"
      ],
      "glosses": [
        "In a theodolite, etc., one of the horizontal crosshairs equidistant from the central horizontal crosshair."
      ],
      "links": [
        [
          "surveying",
          "surveying#Noun"
        ],
        [
          "theodolite",
          "theodolite"
        ],
        [
          "horizontal",
          "horizontal"
        ],
        [
          "crosshair",
          "crosshair"
        ],
        [
          "equidistant",
          "equidistant"
        ]
      ],
      "raw_glosses": [
        "(surveying) In a theodolite, etc., one of the horizontal crosshairs equidistant from the central horizontal crosshair."
      ],
      "topics": [
        "geography",
        "natural-sciences",
        "surveying"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "stadia wire"
    }
  ],
  "word": "stadia hair"
}