"vitesse de la lumière" meaning in French

{
  "forms": [
    {
      "form": "vitesses de la lumière",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f",
        "2": "-",
        "3": "+"
      },
      "expansion": "vitesse de la lumière f (usually uncountable, plural vitesses de la lumière)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "French entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "French terms with collocations",
          "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": "fr",
          "name": "Units of measure",
          "orig": "fr:Units of measure",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              5,
              26
            ]
          ],
          "english": "at the speed of light",
          "text": "à la vitesse de la lumière",
          "type": "example"
        },
        {
          "bold_english_offsets": [
            [
              4,
              18
            ]
          ],
          "bold_text_offsets": [
            [
              3,
              24
            ]
          ],
          "english": "the speed of light in a vacuum.",
          "text": "la vitesse de la lumière dans le vide",
          "type": "example"
        }
      ],
      "glosses": [
        "speed of light (the speed of electromagnetic radiation in a vacuum or in a substance)"
      ],
      "id": "en-vitesse_de_la_lumière-fr-noun-TlEOOsu2",
      "links": [
        [
          "speed of light",
          "speed of light"
        ]
      ],
      "related": [
        {
          "word": "vitesse du son"
        },
        {
          "word": "année-lumière"
        }
      ],
      "tags": [
        "feminine",
        "uncountable",
        "usually"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/vi.tɛs də la ly.mjɛʁ/"
    },
    {
      "audio": "LL-Q150 (fra)-Lyokoï-vitesse de la lumière.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/5/5a/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/5/5a/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav.ogg"
    }
  ],
  "word": "vitesse de la lumière"
}

{
  "forms": [
    {
      "form": "vitesses de la lumière",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f",
        "2": "-",
        "3": "+"
      },
      "expansion": "vitesse de la lumière f (usually uncountable, plural vitesses de la lumière)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "related": [
    {
      "word": "vitesse du son"
    },
    {
      "word": "année-lumière"
    }
  ],
  "senses": [
    {
      "categories": [
        "French countable nouns",
        "French entries with incorrect language header",
        "French feminine nouns",
        "French lemmas",
        "French multiword terms",
        "French nouns",
        "French terms with IPA pronunciation",
        "French terms with collocations",
        "French uncountable nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "fr:Units of measure"
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              5,
              26
            ]
          ],
          "english": "at the speed of light",
          "text": "à la vitesse de la lumière",
          "type": "example"
        },
        {
          "bold_english_offsets": [
            [
              4,
              18
            ]
          ],
          "bold_text_offsets": [
            [
              3,
              24
            ]
          ],
          "english": "the speed of light in a vacuum.",
          "text": "la vitesse de la lumière dans le vide",
          "type": "example"
        }
      ],
      "glosses": [
        "speed of light (the speed of electromagnetic radiation in a vacuum or in a substance)"
      ],
      "links": [
        [
          "speed of light",
          "speed of light"
        ]
      ],
      "tags": [
        "feminine",
        "uncountable",
        "usually"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/vi.tɛs də la ly.mjɛʁ/"
    },
    {
      "audio": "LL-Q150 (fra)-Lyokoï-vitesse de la lumière.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/5/5a/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/5/5a/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-vitesse_de_la_lumi%C3%A8re.wav.ogg"
    }
  ],
  "word": "vitesse de la lumière"
}