"sub-light" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "sub",
        "3": "light"
      },
      "expansion": "sub- + light",
      "name": "prefix"
    }
  ],
  "etymology_text": "sub- + light",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "sub-light (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms prefixed with sub-",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Light",
          "orig": "en:Light",
          "parents": [
            "Energy",
            "Nature",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Relativity",
          "orig": "en:Relativity",
          "parents": [
            "Physics",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Science fiction",
          "orig": "en:Science fiction",
          "parents": [
            "Fiction",
            "Speculative fiction",
            "Artistic works",
            "Genres",
            "Art",
            "Entertainment",
            "Culture",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2017, A.K. Brown, Humans on the Menu (Champagne Universe Series: Book 2), page 36",
          "text": "We are about to test sub-light engine disengage.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "At less than the speed of light."
      ],
      "id": "en-sub-light-en-adj-tlg6KbKY",
      "links": [
        [
          "science fiction",
          "science fiction"
        ],
        [
          "speed of light",
          "speed of light"
        ]
      ],
      "raw_glosses": [
        "(science fiction) At less than the speed of light."
      ],
      "synonyms": [
        {
          "word": "sublight"
        }
      ],
      "tags": [
        "not-comparable"
      ],
      "topics": [
        "literature",
        "media",
        "publishing",
        "science-fiction"
      ]
    }
  ],
  "word": "sub-light"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "sub",
        "3": "light"
      },
      "expansion": "sub- + light",
      "name": "prefix"
    }
  ],
  "etymology_text": "sub- + light",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "sub-light (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        "English adjectives",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English terms prefixed with sub-",
        "English terms with quotations",
        "English uncomparable adjectives",
        "en:Light",
        "en:Relativity",
        "en:Science fiction"
      ],
      "examples": [
        {
          "ref": "2017, A.K. Brown, Humans on the Menu (Champagne Universe Series: Book 2), page 36",
          "text": "We are about to test sub-light engine disengage.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "At less than the speed of light."
      ],
      "links": [
        [
          "science fiction",
          "science fiction"
        ],
        [
          "speed of light",
          "speed of light"
        ]
      ],
      "raw_glosses": [
        "(science fiction) At less than the speed of light."
      ],
      "tags": [
        "not-comparable"
      ],
      "topics": [
        "literature",
        "media",
        "publishing",
        "science-fiction"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "sublight"
    }
  ],
  "word": "sub-light"
}