"langue d'oïl" meaning in French

{
  "etymology_templates": [
    {
      "args": {
        "1": "fr",
        "2": "fro",
        "3": "-"
      },
      "expansion": "Old French",
      "name": "uder"
    }
  ],
  "etymology_text": "From the Old French word oïl (“yes”). Compare langue d’oc and langue de si.",
  "forms": [
    {
      "form": "langue d’ oïl",
      "tags": [
        "canonical",
        "feminine"
      ]
    },
    {
      "form": "langues d’oïl",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "langue d’oïl f (plural langues d’oïl)",
      "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"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "French undefined derivations",
          "parents": [
            "Undefined derivations",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "fr",
          "name": "Languages",
          "orig": "fr:Languages",
          "parents": [
            "Language",
            "Names",
            "Communication",
            "All topics",
            "Proper nouns",
            "Terms by semantic function",
            "Fundamental",
            "Nouns",
            "Lemmas"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "any of the Old French dialects, spoken in the north of France during the Middle Ages"
      ],
      "id": "en-langue_d'oïl-fr-noun-9iKyuqnP",
      "links": [
        [
          "Old French",
          "Old French"
        ]
      ],
      "related": [
        {
          "word": "oïlique"
        },
        {
          "word": "langue d’oc"
        },
        {
          "word": "langue de si"
        }
      ],
      "synonyms": [
        {
          "word": "ancien français"
        },
        {
          "word": ";"
        },
        {
          "word": "vieux français"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/lɑ̃ɡ d‿ɔjl/"
    }
  ],
  "word": "langue d'oïl"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "fr",
        "2": "fro",
        "3": "-"
      },
      "expansion": "Old French",
      "name": "uder"
    }
  ],
  "etymology_text": "From the Old French word oïl (“yes”). Compare langue d’oc and langue de si.",
  "forms": [
    {
      "form": "langue d’ oïl",
      "tags": [
        "canonical",
        "feminine"
      ]
    },
    {
      "form": "langues d’oïl",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f"
      },
      "expansion": "langue d’oïl f (plural langues d’oïl)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "related": [
    {
      "word": "oïlique"
    },
    {
      "word": "langue d’oc"
    },
    {
      "word": "langue de si"
    }
  ],
  "senses": [
    {
      "categories": [
        "French countable nouns",
        "French entries with incorrect language header",
        "French feminine nouns",
        "French lemmas",
        "French multiword terms",
        "French nouns",
        "French terms derived from Old French",
        "French terms with IPA pronunciation",
        "French undefined derivations",
        "fr:Languages"
      ],
      "glosses": [
        "any of the Old French dialects, spoken in the north of France during the Middle Ages"
      ],
      "links": [
        [
          "Old French",
          "Old French"
        ]
      ],
      "synonyms": [
        {
          "word": "ancien français"
        },
        {
          "word": ";"
        },
        {
          "word": "vieux français"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/lɑ̃ɡ d‿ɔjl/"
    }
  ],
  "word": "langue d'oïl"
}