"treizième mois" meaning in French

{
  "etymology_templates": [
    {
      "args": {
        "1": "thirteenth month"
      },
      "expansion": "“thirteenth month”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "thirteenth month"
      },
      "expansion": "Literally, “thirteenth month”",
      "name": "lit"
    },
    {
      "args": {
        "1": "pl",
        "2": "trzynastka"
      },
      "expansion": "Polish trzynastka",
      "name": "cog"
    },
    {
      "args": {
        "1": "nl",
        "2": "dertiende maand"
      },
      "expansion": "Dutch dertiende maand",
      "name": "cog"
    }
  ],
  "etymology_text": "Literally, “thirteenth month”. Compare Polish trzynastka, Dutch dertiende maand.",
  "forms": [
    {
      "form": "treizièmes mois",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "treizième mois m (plural treizièmes mois)",
      "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"
        },
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          "name": "Pages with 1 entry",
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        },
        {
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        }
      ],
      "glosses": [
        "extra month's salary, annual bonus equal to a month's salary"
      ],
      "id": "en-treizième_mois-fr-noun-rhIFT0s0",
      "links": [
        [
          "month",
          "month"
        ],
        [
          "salary",
          "salary"
        ],
        [
          "annual",
          "annual"
        ],
        [
          "bonus",
          "bonus"
        ]
      ],
      "tags": [
        "masculine"
      ],
      "wikipedia": [
        "fr:treizième mois"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/tʁɛ.zjɛm mwa/"
    },
    {
      "audio": "LL-Q150 (fra)-WikiLucas00-treizième mois.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/6/6b/LL-Q150_%28fra%29-WikiLucas00-treizi%C3%A8me_mois.wav/LL-Q150_%28fra%29-WikiLucas00-treizi%C3%A8me_mois.wav.mp3",
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    }
  ],
  "word": "treizième mois"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "thirteenth month"
      },
      "expansion": "“thirteenth month”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "thirteenth month"
      },
      "expansion": "Literally, “thirteenth month”",
      "name": "lit"
    },
    {
      "args": {
        "1": "pl",
        "2": "trzynastka"
      },
      "expansion": "Polish trzynastka",
      "name": "cog"
    },
    {
      "args": {
        "1": "nl",
        "2": "dertiende maand"
      },
      "expansion": "Dutch dertiende maand",
      "name": "cog"
    }
  ],
  "etymology_text": "Literally, “thirteenth month”. Compare Polish trzynastka, Dutch dertiende maand.",
  "forms": [
    {
      "form": "treizièmes mois",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "treizième mois m (plural treizièmes mois)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "French countable nouns",
        "French entries with incorrect language header",
        "French lemmas",
        "French masculine nouns",
        "French multiword terms",
        "French nouns",
        "French nouns with red links in their headword lines",
        "French terms with IPA pronunciation",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "extra month's salary, annual bonus equal to a month's salary"
      ],
      "links": [
        [
          "month",
          "month"
        ],
        [
          "salary",
          "salary"
        ],
        [
          "annual",
          "annual"
        ],
        [
          "bonus",
          "bonus"
        ]
      ],
      "tags": [
        "masculine"
      ],
      "wikipedia": [
        "fr:treizième mois"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/tʁɛ.zjɛm mwa/"
    },
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  ],
  "word": "treizième mois"
}