"le leur" meaning in French

{
  "forms": [
    {
      "form": "la leur",
      "tags": [
        "feminine"
      ]
    },
    {
      "form": "les leurs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "f": "la leur",
        "p": "les leurs"
      },
      "expansion": "le leur m (feminine la leur, plural les leurs)",
      "name": "fr-pron"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "pron",
  "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 possessive pronouns",
          "parents": [
            "Possessive pronouns",
            "Pronouns",
            "Lemmas"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "French pronouns",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "english": "No, that's not their son. Theirs is younger.",
          "text": "Non, ce n’est pas leur fils. Le leur est plus jeune.",
          "type": "example"
        }
      ],
      "glosses": [
        "theirs (the one belonging to them)"
      ],
      "id": "en-le_leur-fr-pron-U2cWdF7P",
      "links": [
        [
          "theirs",
          "theirs"
        ]
      ],
      "related": [
        {
          "word": "leur"
        }
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/lə lœʁ/"
    }
  ],
  "word": "le leur"
}

{
  "forms": [
    {
      "form": "la leur",
      "tags": [
        "feminine"
      ]
    },
    {
      "form": "les leurs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "f": "la leur",
        "p": "les leurs"
      },
      "expansion": "le leur m (feminine la leur, plural les leurs)",
      "name": "fr-pron"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "pron",
  "related": [
    {
      "word": "leur"
    }
  ],
  "senses": [
    {
      "categories": [
        "French entries with incorrect language header",
        "French lemmas",
        "French multiword terms",
        "French possessive pronouns",
        "French pronouns",
        "French terms with IPA pronunciation",
        "French terms with usage examples"
      ],
      "examples": [
        {
          "english": "No, that's not their son. Theirs is younger.",
          "text": "Non, ce n’est pas leur fils. Le leur est plus jeune.",
          "type": "example"
        }
      ],
      "glosses": [
        "theirs (the one belonging to them)"
      ],
      "links": [
        [
          "theirs",
          "theirs"
        ]
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/lə lœʁ/"
    }
  ],
  "word": "le leur"
}