business holiday; day off for a business
Refers to a day when a business or establishment is closed, such as a regular closing day or a special holiday.
この店の休業日は毎週火曜日です。
This shop's business holiday is every Tuesday.
年末年始は休業日となります。
We will be closed for the year-end and New Year holidays.
休業日 is a general term for any day a business is closed, whether temporary or irregular, while 定休日 refers specifically to a fixed, recurring closing day.
休業日 is a general term for any day a business is closed, whereas 休館日 is used specifically for facilities like libraries or museums.
Compound of 休業 (kyūgyō, 'business closure') + 日 (bi, 'day').