regular holiday; fixed day off; regular closing day
Abbreviation of 定休日. Used for a business's scheduled weekly closing day or a regular day off.
See also: 定休日 (ていきゅうび)
This shop's regular closing day is every Tuesday.
Let's check the salon's fixed day off before going.
Our shop's regular closing day is Monday.
We are closed today due to our regular closing day.