business day; working day
Refers to a day when a business or office is open. Also used as a counter for the number of business days.
当店の営業日は月曜日から金曜日です。
Our business days are Monday through Friday.
It takes three business days to ship.
営業時間 is the hours within a day that a business is open, whereas 営業日 is a whole day on which the business operates.
Compound of 営業 (business, operations) and 日 (day). The reading is the standard on'yomi combination.