"fit note" meaning in English

{
  "forms": [
    {
      "form": "fit notes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "fit note (plural fit notes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "British English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "coordinate_terms": [
        {
          "word": "sick note"
        }
      ],
      "glosses": [
        "A note issued by a doctor, indicating whether the patient is fit to work and under what conditions."
      ],
      "id": "en-fit_note-en-noun-x7eiyT2n",
      "links": [
        [
          "doctor",
          "doctor"
        ],
        [
          "patient",
          "patient"
        ],
        [
          "fit",
          "fit"
        ],
        [
          "work",
          "work"
        ]
      ],
      "raw_glosses": [
        "(UK) A note issued by a doctor, indicating whether the patient is fit to work and under what conditions."
      ],
      "tags": [
        "UK"
      ]
    }
  ],
  "word": "fit note"
}

{
  "coordinate_terms": [
    {
      "word": "sick note"
    }
  ],
  "forms": [
    {
      "form": "fit notes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "fit note (plural fit notes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "British English",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "A note issued by a doctor, indicating whether the patient is fit to work and under what conditions."
      ],
      "links": [
        [
          "doctor",
          "doctor"
        ],
        [
          "patient",
          "patient"
        ],
        [
          "fit",
          "fit"
        ],
        [
          "work",
          "work"
        ]
      ],
      "raw_glosses": [
        "(UK) A note issued by a doctor, indicating whether the patient is fit to work and under what conditions."
      ],
      "tags": [
        "UK"
      ]
    }
  ],
  "word": "fit note"
}