"diurnal arc" meaning in English

{
  "forms": [
    {
      "form": "diurnal arcs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "diurnal arc (plural diurnal arcs)",
      "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": "Astrology",
          "orig": "en:Astrology",
          "parents": [
            "Divination",
            "Pseudoscience",
            "Occult",
            "Sciences",
            "Forteana",
            "Religion",
            "All topics",
            "Culture",
            "Fundamental",
            "Society"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "the path followed by a planet, point, or degree from its rising point to its setting point."
      ],
      "id": "en-diurnal_arc-en-noun-0gHFXbLw",
      "links": [
        [
          "astrology",
          "astrology"
        ],
        [
          "planet",
          "planet"
        ]
      ],
      "raw_glosses": [
        "(astrology) the path followed by a planet, point, or degree from its rising point to its setting point."
      ],
      "topics": [
        "astrology",
        "human-sciences",
        "mysticism",
        "philosophy",
        "sciences"
      ],
      "translations": [
        {
          "code": "ko",
          "lang": "Korean",
          "roman": "iljuho",
          "sense": "path from the rising point to the setting point",
          "word": "일주호"
        }
      ]
    }
  ],
  "word": "diurnal arc"
}

{
  "forms": [
    {
      "form": "diurnal arcs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "diurnal arc (plural diurnal arcs)",
      "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:Astrology"
      ],
      "glosses": [
        "the path followed by a planet, point, or degree from its rising point to its setting point."
      ],
      "links": [
        [
          "astrology",
          "astrology"
        ],
        [
          "planet",
          "planet"
        ]
      ],
      "raw_glosses": [
        "(astrology) the path followed by a planet, point, or degree from its rising point to its setting point."
      ],
      "topics": [
        "astrology",
        "human-sciences",
        "mysticism",
        "philosophy",
        "sciences"
      ]
    }
  ],
  "translations": [
    {
      "code": "ko",
      "lang": "Korean",
      "roman": "iljuho",
      "sense": "path from the rising point to the setting point",
      "word": "일주호"
    }
  ],
  "word": "diurnal arc"
}