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.
This shop's business holiday is every Tuesday.
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, whereas 休館日 is used specifically for facilities like libraries or museums.
Compound of 休業 (kyūgyō, 'business closure') + 日 (bi, 'day').