"Sol IV" meaning in English

{
  "etymology_text": "From its position as the fourth planet out from the Sun (Sol).",
  "head_templates": [
    {
      "args": {
        "head": "Sol IV"
      },
      "expansion": "Sol IV",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "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": "Mars (planet)",
          "orig": "en:Mars (planet)",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Science fiction",
          "orig": "en:Science fiction",
          "parents": [],
          "source": "w"
        }
      ],
      "coordinate_terms": [
        {
          "word": "Sol"
        },
        {
          "word": "Sol I"
        },
        {
          "word": "Sol II"
        },
        {
          "word": "Sol III"
        },
        {
          "word": "Sol V"
        },
        {
          "word": "Sol VI"
        },
        {
          "word": "Sol VII"
        },
        {
          "word": "Sol VIII"
        },
        {
          "word": "Sol IX"
        },
        {
          "word": "Sol X"
        }
      ],
      "glosses": [
        "The planet Mars."
      ],
      "id": "en-Sol_IV-en-name-DxbkQTn8",
      "links": [
        [
          "science fiction",
          "science fiction"
        ],
        [
          "Mars",
          "Mars"
        ]
      ],
      "raw_glosses": [
        "(poetic, science fiction) The planet Mars."
      ],
      "tags": [
        "poetic"
      ],
      "topics": [
        "literature",
        "media",
        "publishing",
        "science-fiction"
      ]
    }
  ],
  "word": "Sol IV"
}

{
  "coordinate_terms": [
    {
      "word": "Sol"
    },
    {
      "word": "Sol I"
    },
    {
      "word": "Sol II"
    },
    {
      "word": "Sol III"
    },
    {
      "word": "Sol V"
    },
    {
      "word": "Sol VI"
    },
    {
      "word": "Sol VII"
    },
    {
      "word": "Sol VIII"
    },
    {
      "word": "Sol IX"
    },
    {
      "word": "Sol X"
    }
  ],
  "etymology_text": "From its position as the fourth planet out from the Sun (Sol).",
  "head_templates": [
    {
      "args": {
        "head": "Sol IV"
      },
      "expansion": "Sol IV",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English poetic terms",
        "English proper nouns",
        "English terms containing Roman numerals",
        "English uncountable nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Mars (planet)",
        "en:Science fiction"
      ],
      "glosses": [
        "The planet Mars."
      ],
      "links": [
        [
          "science fiction",
          "science fiction"
        ],
        [
          "Mars",
          "Mars"
        ]
      ],
      "raw_glosses": [
        "(poetic, science fiction) The planet Mars."
      ],
      "tags": [
        "poetic"
      ],
      "topics": [
        "literature",
        "media",
        "publishing",
        "science-fiction"
      ]
    }
  ],
  "word": "Sol IV"
}