"de mémoire" meaning in French

{
  "head_templates": [
    {
      "args": {},
      "expansion": "de mémoire",
      "name": "fr-adv"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "adv",
  "related": [
    {
      "_dis1": "0 0",
      "word": "de mémoire d’homme"
    },
    {
      "_dis1": "0 0",
      "word": "par cœur"
    }
  ],
  "senses": [
    {
      "categories": [
        {
          "_dis": "51 49",
          "kind": "other",
          "name": "French entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "53 47",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "53 47",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "57 43",
          "kind": "topical",
          "langcode": "fr",
          "name": "Memory",
          "orig": "fr:Memory",
          "parents": [
            "Mind",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "from memory"
      ],
      "id": "en-de_mémoire-fr-adv-5FRNoSPh",
      "links": [
        [
          "from memory",
          "from memory"
        ]
      ]
    },
    {
      "categories": [
        {
          "_dis": "51 49",
          "kind": "other",
          "name": "French entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
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          "source": "w+disamb"
        },
        {
          "_dis": "53 47",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "53 47",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "examples": [
        {
          "english": "From memory, I would say that this happened in 1831.",
          "text": "De mémoire, je dirais que ça s’est passé en 1831.",
          "type": "example"
        }
      ],
      "glosses": [
        "if memory serves"
      ],
      "id": "en-de_mémoire-fr-adv-MgJDmhHe",
      "links": [
        [
          "if memory serves",
          "if memory serves"
        ]
      ],
      "synonyms": [
        {
          "word": "si ma mémoire est bonne"
        },
        {
          "word": "de tête"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/də me.mwaʁ/"
    },
    {
      "audio": "LL-Q150 (fra)-WikiLucas00-de mémoire.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/6/6b/LL-Q150_%28fra%29-WikiLucas00-de_m%C3%A9moire.wav/LL-Q150_%28fra%29-WikiLucas00-de_m%C3%A9moire.wav.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/6/6b/LL-Q150_%28fra%29-WikiLucas00-de_m%C3%A9moire.wav/LL-Q150_%28fra%29-WikiLucas00-de_m%C3%A9moire.wav.ogg"
    }
  ],
  "word": "de mémoire"
}

{
  "categories": [
    "French adverbs",
    "French entries with incorrect language header",
    "French lemmas",
    "French multiword terms",
    "French terms with IPA pronunciation",
    "Pages with 1 entry",
    "Pages with entries",
    "fr:Memory"
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "de mémoire",
      "name": "fr-adv"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "adv",
  "related": [
    {
      "word": "de mémoire d’homme"
    },
    {
      "word": "par cœur"
    }
  ],
  "senses": [
    {
      "glosses": [
        "from memory"
      ],
      "links": [
        [
          "from memory",
          "from memory"
        ]
      ]
    },
    {
      "categories": [
        "French terms with usage examples"
      ],
      "examples": [
        {
          "english": "From memory, I would say that this happened in 1831.",
          "text": "De mémoire, je dirais que ça s’est passé en 1831.",
          "type": "example"
        }
      ],
      "glosses": [
        "if memory serves"
      ],
      "links": [
        [
          "if memory serves",
          "if memory serves"
        ]
      ],
      "synonyms": [
        {
          "word": "si ma mémoire est bonne"
        },
        {
          "word": "de tête"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/də me.mwaʁ/"
    },
    {
      "audio": "LL-Q150 (fra)-WikiLucas00-de mémoire.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/6/6b/LL-Q150_%28fra%29-WikiLucas00-de_m%C3%A9moire.wav/LL-Q150_%28fra%29-WikiLucas00-de_m%C3%A9moire.wav.mp3",
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    }
  ],
  "word": "de mémoire"
}