A day when a hospital or clinic does not hold consultations; a day when outpatient services are closed.
この病院は日曜が休診日です。
This hospital is closed for consultations on Sundays.
休診日のため、予約の変更は月曜日にお願いします。
Because it's a closed day, please make appointment changes on Monday.
小児科は第2・第4水曜を休診日にしている。
The pediatrics department is closed on the 2nd and 4th Wednesdays.