"lettres classiques" meaning in French

{
  "head_templates": [
    {
      "args": {
        "1": "f-p"
      },
      "expansion": "lettres classiques f pl (plural only)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "French entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
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          "source": "w"
        },
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          "kind": "other",
          "name": "French pluralia tantum",
          "parents": [
            "Pluralia tantum",
            "Nouns",
            "Lemmas"
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          "source": "w"
        },
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          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "fr",
          "name": "Classical studies",
          "orig": "fr:Classical studies",
          "parents": [
            "History",
            "Linguistics",
            "Literature",
            "All topics",
            "Language",
            "Social sciences",
            "Culture",
            "Entertainment",
            "Writing",
            "Fundamental",
            "Communication",
            "Sciences",
            "Society",
            "Human behaviour",
            "Human"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "classical studies (the study of Ancient Greek and Latin, their literature, history, etc.)"
      ],
      "id": "en-lettres_classiques-fr-noun-gDJCmM2o",
      "links": [
        [
          "classical studies",
          "classical studies"
        ]
      ],
      "tags": [
        "feminine",
        "plural",
        "plural-only"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/lɛ.tʁə kla.sik/"
    },
    {
      "ipa": "/le.tʁə kla.sik/"
    }
  ],
  "word": "lettres classiques"
}

{
  "head_templates": [
    {
      "args": {
        "1": "f-p"
      },
      "expansion": "lettres classiques f pl (plural only)",
      "name": "fr-noun"
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  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
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        "French entries with incorrect language header",
        "French feminine nouns",
        "French lemmas",
        "French multiword terms",
        "French nouns",
        "French pluralia tantum",
        "French terms with IPA pronunciation",
        "Pages with 1 entry",
        "Pages with entries",
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      ],
      "glosses": [
        "classical studies (the study of Ancient Greek and Latin, their literature, history, etc.)"
      ],
      "links": [
        [
          "classical studies",
          "classical studies"
        ]
      ],
      "tags": [
        "feminine",
        "plural",
        "plural-only"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/lɛ.tʁə kla.sik/"
    },
    {
      "ipa": "/le.tʁə kla.sik/"
    }
  ],
  "word": "lettres classiques"
}