"cosmic event horizon" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "cosmic",
        "3": "event horizon"
      },
      "expansion": "cosmic + event horizon",
      "name": "compound"
    }
  ],
  "etymology_text": "cosmic + event horizon",
  "forms": [
    {
      "form": "cosmic event horizons",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "cosmic event horizon"
      },
      "expansion": "cosmic event horizon (plural cosmic event horizons)",
      "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": "Cosmology",
          "orig": "en:Cosmology",
          "parents": [
            "Astronomy",
            "Sciences",
            "Space",
            "All topics",
            "Nature",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "The cosmological horizon; the edge of the observable universe."
      ],
      "id": "en-cosmic_event_horizon-en-noun-xv-xw~xS",
      "links": [
        [
          "cosmological horizon",
          "cosmological horizon"
        ],
        [
          "observable universe",
          "observable universe"
        ]
      ]
    }
  ],
  "word": "cosmic event horizon"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "cosmic",
        "3": "event horizon"
      },
      "expansion": "cosmic + event horizon",
      "name": "compound"
    }
  ],
  "etymology_text": "cosmic + event horizon",
  "forms": [
    {
      "form": "cosmic event horizons",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "cosmic event horizon"
      },
      "expansion": "cosmic event horizon (plural cosmic event horizons)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English compound terms",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Cosmology"
      ],
      "glosses": [
        "The cosmological horizon; the edge of the observable universe."
      ],
      "links": [
        [
          "cosmological horizon",
          "cosmological horizon"
        ],
        [
          "observable universe",
          "observable universe"
        ]
      ]
    }
  ],
  "word": "cosmic event horizon"
}