"単線" meaning in 日本語

{
  "categories": [
    {
      "kind": "other",
      "name": "日本語",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "日本語 名詞",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "たんせん"
    }
  ],
  "lang": "日本語",
  "lang_code": "ja",
  "pos": "noun",
  "pos_title": "名詞",
  "related": [
    {
      "word": "単線並列"
    },
    {
      "word": "複線"
    }
  ],
  "senses": [
    {
      "glosses": [
        "一本の線。"
      ],
      "id": "ja-単線-ja-noun-vOCqyZe5"
    },
    {
      "glosses": [
        "鉄道で上下線の列車が一本の軌道を使用すること。単線軌道。"
      ],
      "id": "ja-単線-ja-noun-aOV1yGDi"
    }
  ],
  "word": "単線"
}

{
  "categories": [
    "日本語",
    "日本語 名詞"
  ],
  "forms": [
    {
      "form": "たんせん"
    }
  ],
  "lang": "日本語",
  "lang_code": "ja",
  "pos": "noun",
  "pos_title": "名詞",
  "related": [
    {
      "word": "単線並列"
    },
    {
      "word": "複線"
    }
  ],
  "senses": [
    {
      "glosses": [
        "一本の線。"
      ]
    },
    {
      "glosses": [
        "鉄道で上下線の列車が一本の軌道を使用すること。単線軌道。"
      ]
    }
  ],
  "word": "単線"
}