"light metro" meaning in English

{
  "etymology_text": "From light and metro (train system).",
  "forms": [
    {
      "form": "light metros",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "light metro (plural light metros)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Rail transportation",
          "orig": "en:Rail transportation",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "An urban rail system with no street crossings or mixed traffic and often complete automation."
      ],
      "id": "en-light_metro-en-noun-j1Vqar7p",
      "links": [
        [
          "automation",
          "automation"
        ]
      ],
      "related": [
        {
          "word": "light rail"
        }
      ]
    }
  ],
  "word": "light metro"
}

{
  "etymology_text": "From light and metro (train system).",
  "forms": [
    {
      "form": "light metros",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "light metro (plural light metros)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "light rail"
    }
  ],
  "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",
        "en:Rail transportation"
      ],
      "glosses": [
        "An urban rail system with no street crossings or mixed traffic and often complete automation."
      ],
      "links": [
        [
          "automation",
          "automation"
        ]
      ]
    }
  ],
  "word": "light metro"
}