regular holiday; fixed closing day
Refers to a business's scheduled day off each week or month, such as a restaurant's regular closing day. Common in signs and business information.
This shop's regular holiday is every Tuesday.
You should check the regular closing day before you go.
This café's regular closing day is Tuesday.
We're closed today because it's our regular closing day.
I checked the shop's regular closing day before going.
Many shops set Wednesday as their regular closing day.
定休日 refers to a regular fixed closing day, the opposite of 年中無休 which means there are no closing days at all.