"distance line" meaning in English

{
  "forms": [
    {
      "form": "distance lines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "distance line (plural distance lines)",
      "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": "Diving",
          "orig": "en:Diving",
          "parents": [
            "Water sports",
            "Sports",
            "Human activity",
            "Human behaviour",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "a rope used by scuba divers as a means of returning to a safe starting point in conditions of low visibility, water currents or where pilotage is difficult."
      ],
      "id": "en-distance_line-en-noun-jH6I3elJ",
      "links": [
        [
          "diving",
          "diving#Noun"
        ],
        [
          "rope",
          "rope"
        ],
        [
          "scuba diver",
          "scuba diver"
        ]
      ],
      "raw_glosses": [
        "(diving) a rope used by scuba divers as a means of returning to a safe starting point in conditions of low visibility, water currents or where pilotage is difficult."
      ],
      "synonyms": [
        {
          "word": "penetration line"
        },
        {
          "word": "cave line"
        },
        {
          "word": "guide line"
        }
      ],
      "topics": [
        "diving",
        "hobbies",
        "lifestyle",
        "sports"
      ]
    }
  ],
  "word": "distance line"
}

{
  "forms": [
    {
      "form": "distance lines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "distance line (plural distance lines)",
      "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:Diving"
      ],
      "glosses": [
        "a rope used by scuba divers as a means of returning to a safe starting point in conditions of low visibility, water currents or where pilotage is difficult."
      ],
      "links": [
        [
          "diving",
          "diving#Noun"
        ],
        [
          "rope",
          "rope"
        ],
        [
          "scuba diver",
          "scuba diver"
        ]
      ],
      "raw_glosses": [
        "(diving) a rope used by scuba divers as a means of returning to a safe starting point in conditions of low visibility, water currents or where pilotage is difficult."
      ],
      "synonyms": [
        {
          "word": "penetration line"
        },
        {
          "word": "cave line"
        },
        {
          "word": "guide line"
        }
      ],
      "topics": [
        "diving",
        "hobbies",
        "lifestyle",
        "sports"
      ]
    }
  ],
  "word": "distance line"
}